Contents · 2020. 6. 19. · • urinalysis – chemical analysis of urine. ... automation...

MSL975037 Perform chemical pathology tests

Study Guide v1.1 June 2020 Page 1 of 23

Contents

INTRODUCTION ............................................................................................................................................ 2

PROCESS SAMPLES AND ASSOCIATED REQUEST FORMS.................................................................. 3

IDENTIFY SPECIMENS AND REQUEST FORMS THAT DO NOT COMPLY WITH MINIMUM INDUSTRY REQUIREMENTS FOR LABELLING, IDENTIFICATION AND TEST REQUESTS ........................................................................................... 3

RECORD ANY DISCREPANCIES AND INDICATE WHAT ACTION IS REQUIRED .......................................................... 4

LOG SAMPLES, RECORDING DETAILS THAT ALLOW ACCURATE TRACKING AND CHAIN OF CUSTODY ...................... 4

PERFORM TESTS ......................................................................................................................................... 6

SELECT AUTHORISED TESTS INDICATED FOR THE REQUESTED INVESTIGATIONS ................................................ 6

COMMON CHEMICAL PATHOLOGY TESTS ......................................................................................................... 7

CONDUCT INDIVIDUAL TESTS, OR BATCHES OF TESTS, ACCORDING TO DOCUMENTED METHODOLOGIES, APPLYING REQUIRED QUALITY CONTROL PROCEDURES ................................................................................................. 12

MANAGE TASKS AND ORGANISE WORK TO ENSURE EFFICIENT USE OF TIME ..................................................... 13

FLAG TEST RESULTS THAT ARE OUTSIDE ACCEPTED QUALITY CONTROL LIMITS ................................................ 13

APPLY QUALITY CONTROL PROCESSES TO DISCRIMINATE BETWEEN SIGNIFICANT DATA AND ARTEFACT ............. 14

CONFIRM WITH SUPERVISOR ANY FURTHER TESTING REQUIREMENTS ............................................................. 16

RECORD ALL TEST DATA, NOTING ANY PHENOMENA THAT MAY BE RELEVANT TO THE TREATMENT OF DATA OR THE INTERPRETATION OF RESULTS ...................................................................................................................... 16

MAINTAIN LABORATORY RECORDS ....................................................................................................... 17

RECORD ENTRIES ON REPORT FORMS OR INTO A LABORATORY INFORMATION MANAGEMENT SYSTEM, ACCURATELY CALCULATING, RECORDING OR TRANSCRIBING DATA AS REQUIRED ............................................. 17

ENSURE SAMPLES AND ASSOCIATED PAPERWORK MAINTAIN TRACEABILITY THROUGHOUT TESTING .................. 18

LEGAL AND ETHICAL RESPONSIBILITIES ......................................................................................................... 19

ENVIRONMENTAL SUSTAINABILITY ................................................................................................................ 20

BIBLIOGRAPHY .......................................................................................................................................... 21

DOCUMENT REVISION ............................................................................................................................... 23



Introduction

Anatomy is the study of the structure of organisms and their parts, and humans have many parts that don’t always function or look in what would be referred to as a standard way.

Biological systems are inherently prone to abnormal anatomy, with some being innocuous, such as the case of unusually long heel bones (calcanei) giving calf muscles superior leverage and has been observed in successful sprinters for years (Ingraham, 2019). Other cases are more serious such as spina bifida where there is incomplete closing of the spine and membranes around the spinal cord during early development which can result in mild to severe physical and intellectual disabilities (Centers for Disease Control and Prevention, 2019).

Chemical pathology is the study of chemical and biochemical mechanisms of the body relating to disease, through the use of chemicals present in body fluids (such as blood or urine) and tissues.

Normal chemical levels are based on averages from numerous patients or based on an individual’s historical levels. Many diseases cause significant changes in the chemical composition of body fluids including raised blood enzymes due to their release from heart muscles after a heart attack, or increased blood sugar in diabetes mellitus due to lack of insulin.

Chemical pathology involves (Pūtaiao, 2019):

• general or routine chemistry – common blood chemistries such as electrolytes, blood gases, lipids, liver and kidney function tests.

• special chemistry – more elaborate techniques such as electrophoresis and manual testing methods.

• clinical endocrinology – the study of hormones and diagnosis of endocrine disorders.

• detection and measurement of drug levels –

o toxicology - analysis testing of the levels for drugs of abuse and other chemicals, which indicate the medical risk and required treatment.

o therapeutic drug monitoring – measurement of therapeutic medications in blood levels to optimise dosage.

• urinalysis – chemical analysis of urine.

• faecal analysis – commonly done for the detection of gastrointestinal disorders.

• toxin detection – aids in determining the appropriate medical treatment and helps identify patients that would benefit from antibiotic treatment, reducing the unnecessary use of antibiotics.

Gel electrophoresis



• Immunoassays – chemical tests used to detect or quantify a specific substance or analyte in a blood or body fluid sample using an immunological reaction. These tests can be used to detect antigens for the identification of hepatitis B and chlamydia, as well as the detection of antibodies produced in HIV, viral hepatitis and Lyme disease (Advameg Inc, 2020).

The quality of chemical pathology laboratories has increased immensely as technology has improved allowing for more accurate results and shorter turn-around-times. Automation was one of the big advancements in the field allowing for increased productivity, reducing errors and improving safety (Streitberg, et al., 2009). This became possible because of the development of the continuous flow analyser in the 1950’s (Felder, 2014). Currently automation encompasses specimen transportation, sorting, accessioning and inspection.

Process samples and associated request forms

At the completion of this section, you should be able to:

• Identify specimens and request forms that do not comply with minimum industry requirements for labelling, identification and test requests

• Record any discrepancies and indicate what action is required

• Log samples, recording details that allow accurate tracking and chain of custody.

Identify specimens and request forms that do not comply with minimum industry requirements for labelling, identification and test requests Many different samples may arrive at your laboratory for testing and/or examination. No matter how they arrive, a key feature of all samples for testing will be an accompanying request form, card, or sheet.

Before commencing any test work, you are required to check all the details of the request to ensure you have the correct samples and that you know which test methods and equipment are needed.

There will be a routine system in your workplace that tells you what samples or materials are to be tested and what tests are to be done on them. This could be through a Laboratory Information Management System (LIMS), spreadsheet or test sheets with priority dates.

Test sheets may show a unique serial number for each sample enabling you to identify and locate the sample via the serial number on its label. Test sheets may also provide a code, barcode or description of the material that will help in the identification of the sample

Labels and codes on samples should allow you to link the sample to its source (such as a patient), identify what the sample is (cerebrospinal fluid (CSF), serum, semen etc.), determine which samples are to be tested and which tests are to be carried out.



If you identify any sample or request forms that do not comply with minimum industry requirements for labelling, identification and test requests, they must be recorded and reported to your supervisor. Follow your organisation's policies and procedures to record and report.

Record any discrepancies and indicate what action is required Where documentation such as test requests or identifying codes or markers are identified as incorrect or suspected to be incorrect, action must be taken to correct the discrepancy, or to replace the document and/or sample.

Despite all efforts, occasionally the sample is not suitable. This is not always obvious until sample preparation has commenced. Apart from checking that the correct collection vessel has been used, and the correct specimen has been collected, you also need to note the condition of the sample. The trauma that can occur at collection of samples can lead to haemolysis of the serum or plasma sample or a bloodied CSF collection.

There could also be damage to the container in transit. Haemolysis is the rupturing (lysis) of red blood cells (erythrocytes) and the release of their contents (cytoplasm) into surrounding fluid (e.g. blood plasma). Haemolysis can be caused:

• by complications during blood collection such as unsecure line connections, contamination, incorrect needle size, improper tube mixing and incorrectly filled tubes.

• by the effects of mechanical processing.

• by bacterial action in cultured blood specimens.

The affects can include increases in potassium, phosphate, bilirubin, aspartate aminotransferase (AST) and decreases in troponin T and glucose.

If the sample label does not match the request the test cannot be carried out. When samples are not as expected, or appear atypical, immediately record your observations and report them to your supervisor or other appropriate person.

You will need to request an additional sample or samples for testing and reject the faulty samples. Performing tests on faulty samples is a waste of time as the results may be misleading, resulting in a potential misdiagnosis.

Log samples, recording details that allow accurate tracking and chain of custody When samples arrive in your laboratory or are extracted from a patient they should be inspected for quality, and the specific sample data recorded. Your laboratory may use a LIMS or a manual log entry system for this.

Some laboratories may use a combination of systems. This may be due to legal requirements (that is, a particular system must be used by law), laboratory standard or accreditation requirements (ISO/IEC), or simply because there are not any acceptable commercial programs available which are useful for your particular laboratory. MS Excel is another tool for recording sample information.

Normal (N), Slight (1+), Moderate (2+ to 3+) and Grossly (4+)



It is important to check that you are authorised to record information onto the documents in your laboratory. An SOP or quality manual contains details about who can mark documents. Your laboratory may have special procedures for correcting mistakes or illegible recordings.

You should check these with your laboratory supervisor. Some documents may be controlled documents, for example methods or SOPs, and these cannot be amended without approval from the laboratory supervisor and/or quality manager.

It is vital to ensure correct and complete information for ‘chain of custody’ to avoid any doubt about the integrity of specimens. Chain of custody is the chronological documentation showing the collection, transfer, receipt, analysis, storage and disposal of the specimen.

It should be possible to know the entire history of the specimen; from original collection (including who took the sample and who has handled it during its journey to and throughout your laboratory), through to the completion of any test. Confusion over labelling of samples could lead to time wasted through wrong tests being performed, results going to the wrong client or incompatible products being transfused. This can also affect commercial aspects such as billing details and business reputation.

You may be required to add labels or designate identification numbers or codes to the samples. This is to allow for successful sample tracking and to assist in traceability/tracking throughout sample preparation, testing and other stages in your laboratory.

The laboratory’s capacity to protect sensitive information may be required by law or as a condition of registration or accreditation. The procedures and policies relating to security and confidentiality ensure that customers and clients have confidence in the laboratory.

Storage of samples

Biological specimens are fragile and often degrade reasonably quickly when maintained at room temperature and may still lose integrity if they undergo multiple freeze-thaw cycles. Ideal storage temperatures vary depending on the biological material, the solution it is suspended in, the samples intended use and the time it will be stored (Brooks Life Sciences, 2018).

Tissue and organ samples may be preserved via fixation using formalin. The cells may lose their biological function, but the visual appearance of the tissue is preserved. This has been the traditional method of preservation for routine histological examinations that involve paraffin embedding, sectioning (cutting into very thin slices), chemical staining and microscopic examination of the sample.

When a sample is to be examined both for its appearance and certain biological properties, formalin, followed by paraffin embedding cannot be used. Instead a fresh sample must be supplied. This means that the sample must be preserved in some other way.



Another method of preservation involves removing the tissue and immediately freezing it. This must be done quickly to prevent ice crystals from forming as ice crystals will rupture cells. The types of tests that may require a frozen section all have one thing in common: the tissue must be as close to in vivo conditions as possible.

However, one distinct advantage of formalin preservation and paraffin embedding is that infectious agents, such as viruses, and in particular human immunodeficiency virus or HIV, are inactivated by formalin and paraffin embedding. Therefore, those working on highly dangerous tissue material are protected. If a sample is incorrectly prepared or shows sign of deterioration it must be safely disposed of and a new sample requested.

Samples in containers or tubes which are cracked or leaking represent a hazard not only to the collector, but the samples themselves may be contaminated (or have contaminated other samples) and this may affect any examination or test to be performed.

Once damaged or leaking samples are detected, they should be isolated and separated from other samples. The samples which have come into contact with them should also be carefully examined for damage or contamination. Even if samples appear not to be contaminated it should be noted what type of spill, breakage or leakage occurred with other samples in that batch. This way any anomalous results can be explained.

Your workplace/laboratory should have an SOP for isolating and controlling sample leaks, spills. This procedure is in place to minimise the risk of cross-contamination and maintain sample integrity. The procedure may also require you to report these events to your workplace/laboratory supervisor.

Perform tests


• Select authorised tests indicated for the requested investigations

• Conduct individual tests, or batches of tests, according to documented methodologies, applying required quality control procedures

• Manage tasks and organise work to ensure efficient use of time

• Flag test results that are outside accepted quality control limits

• Apply quality control processes to discriminate between significant data and artefact

• Confirm with supervisor any further testing requirements

• Record all test data, noting any phenomena that may be relevant to the treatment of data or the interpretation of results.

Select authorised tests indicated for the requested investigations Chemical pathology as a sub-speciality within pathology that extends across most medical specialities. It involves the chemical analysis of bodily fluids such as blood (whole blood, serum or plasma), urine, cerebrospinal fluid, effusions, seminal fluid, sweat and amniotic fluid to assist in the diagnosis of various disease processes.



There are numerous tests that can be requested for investigation. You must select the tests that have been indicated and then conduct the tests according to documented methodologies, applying required quality control procedures.

The chemical pathologist must understand a wide variety of physico-chemical techniques, be able to solve problems that arise in the laboratory and make informed decisions with regard to the selection of instrumentation.

Common chemical pathology tests

Liver function tests

Liver function tests (LFTs) is a group of tests that are performed together to detect, evaluate, and monitor liver disease or damage. LFTs measure enzymes, proteins, and substances that are produced or excreted by the liver and are affected by liver injury. Some are released by damaged liver cells and some reflect a decrease in the liver's ability to perform one or more of its functions.

When performed together, these tests give the doctor a snapshot of the health of the liver, an indication of the potential severity of any liver injury, change in liver status over time, and a starting place for further diagnostic testing. Examples of tests performed as part of a LFT include:

• Alanine aminotransferase (ALT) test – an enzyme mainly found in the liver; the best test for detecting hepatitis.

• Alkaline phosphatase (ALP) test – an enzyme related to the bile ducts; often increased when they are blocked.

• Aspartate aminotransferase (AST) test – an enzyme found in the liver and a few other places, particularly the heart and other muscles in the body.

• Total bilirubin test – measures all the yellow bilirubin pigment in the blood. Another test, direct bilirubin, measures a form combined with another compound in the liver and is often requested with total bilirubin in infants with jaundice.

• Albumin test – measures the amount of albumin in your blood which is the main protein made by the liver and tells whether or not the liver is making an adequate amount.

• Gamma-glutamyl transferase (GGT) test - an enzyme found mainly in the liver and is a useful marker for detecting bile duct problems.

• Total protein test - measures albumin and all other proteins in blood, including antibodies made to help fight off infections. An increased result can be due to multiple myeloma, dehydration, chronic liver disease, chronic inflammation or infection. A decreased result can be due to malnutrition, severe liver disease, water overload, nephrotic syndrome, or protein-losing enteropathy.

LFT results are not diagnostic of a specific condition; they indicate that there may be a problem with the liver. In a person who does not have symptoms or identifiable risk factors, abnormal liver test results may indicate a temporary liver injury or reflect something that is happening elsewhere in the body – such as in the skeletal muscles, pancreas, or heart. It may also indicate early liver disease and the need for further testing and/or periodic monitoring.



Results of LFTs are usually evaluated together. Several sets of results from tests performed over a few days or weeks are often assessed together to determine if a pattern is present. Each person will have a unique set of test results that typically change over time. A doctor evaluates the combination of liver test results to gain clues about the underlying condition. Often, further testing is necessary to determine what is causing the liver damage and/or disease.

The table below shows examples of some combinations of results that may be seen in certain types of liver conditions or diseases.

Type of liver condition or disease

Bilirubin ALT and AST ALP and GGT Albumin

Acute Liver damage (due, for example, to infection, toxins or drugs, etc.)

Normal or increased usually after ALT and AST are already increased

Usually greatly increased; ALT is usually higher than AST

Normal or only moderately increased

Normal

Chronic forms of various liver disorders

Normal or increased

Moderately increased

Normal to slightly increased

Normal

Alcoholic Hepatitis

Normal or increased

AST is usually higher than the level of ALT

Normal or moderately increased, GGT markedly increased

Normal

Cirrhosis May be increased but this usually occurs later in the disease

AST is usually higher than ALT but levels are usually lower than in alcoholic disease

Normal or increased

Usually decreased

Bile duct obstruction, cholestasis

Normal or increased; increased in complete obstruction

Normal to moderately increased

Increased; often greater than 4 times what is normal

Usually normal but if the disease is chronic, levels may decrease

Cancer that has spread to the liver (metastasized)

Usually normal Normal or slightly increased

Usually greatly increased

Normal

Cancer originating in the liver (hepatocellular carcinoma, HCC)

May be increased, especially if the disease has progressed

AST higher than ALT but levels lower than that seen in alcoholic disease

Normal or increased

Usually decreased

Autoimmune Normal or increased

Moderately increased

Normal or slightly increased

Normal or decreased

http://www.labtestsonline.org.au/learning/Glossary/chronichttp://www.labtestsonline.org.au/learning/Index-of-Conditions/hephttp://www.labtestsonline.org.au/learning/Index-of-Conditions/hephttp://www.labtestsonline.org.au/learning/Glossary/cirrhosis



The quantitative human chorionic gonadotropin (hCG) blood test measures the level of hCG hormone present in a sample of blood. hCG is a hormone that is produced during pregnancy and the test is performed to:

• confirm pregnancy

• determine the approximate age of the foetus

• diagnose an abnormal pregnancy, such as an ectopic pregnancy

• diagnose a potential miscarriage

• screen for Down’s syndrome.

Blood tests

A full blood count (FBC) is one of the most commonly ordered tests and provides important information about the kinds and numbers of cells in the blood: red blood cells (RBC), white blood cells (WBC), platelets and mean corpuscular volume (MCV) which is a measurement of the size of RBCs.

Abnormalities in any of these types of cells can indicate the presence of important medical disorders. Anisocytosis is a condition in which the RBCs are

unequal in size. This is commonly found in anaemia and other blood conditions.

The RBCs of an individual contain antigens on their surfaces that correspond to their blood group and antibodies that will attack antigen sites on the surfaces of RBCs of another group. For example, someone with blood type A has the A antigen on its RBCs and antibodies (Anti-B) that will attack RBCs with the B antigen on them. The reaction between RBCs and corresponding antibodies usually results in clumping (agglutination) of the RBCs.

Blood cholesterol testing measuring the level of cholesterol in the blood may be performed if the patient already knows they have heart disease (angina, heart attack), or if there is a family history of heart disease at an early age. An increased result can be due to familial hyperlipidaemia, hypothyroidism, liver disease, renal disease, diabetes mellitus whereas a decreased result can be due to hyperthyroidism, infection, myocardial infarction or inherited hypolipidaemias.

Glucose tolerance test

A glucose tolerance test (GTT) determines whether or not blood glucose levels are within the reference range; to screen for, diagnose, and monitor diabetes and gestational diabetes mellitus (GDM). An increased glucose result can be due to a non-fasting state, diabetes mellitus, infection, excess endogenous or exogenous steroid. A decreased result may be due to excess exogenous or endogenous insulin, early glucose intolerance, adrenal or pituitary failure, severe liver disease or oral hypoglycaemic medication.



DNA testing

Deoxyribonucleic acid (DNA) is a molecule that carries the genetic instructions used in the growth, development, functioning and reproduction of all known living organisms and many viruses. Fluorescence in situ hybridisation (FISH) is a molecular testing method that uses fluorescent probes to evaluate genes and/or DNA sequences on chromosomes.

Immunological tests

Immunological tests can be conducted to detect and measure a number of different components in the body such as drugs, hormones, specific proteins, tumour markers and markers of cardiac injury (Advameg Inc, 2020). These tests all work on the principle of an immunological reaction which is the formation of an antibody-antigen complex. The immune system is one of the main lines of defence for the body and involves the use of white blood cells known as leukocytes.

These leukocytes travel through the bloodstream and into tissues, attacking microorganisms, parasites and other materials the body identifies as foreign (Delves, 2019). To be effective, the immune system must be able to identify what belongs to the body (self) and what does not (foreign).

There are two types of immunity the immune system provides:

• Innate immunity – is an immunity that is present from birth and does not have to be learned through exposure to an invader. The white blood cells involved in innate immunity are monocytes, neutrophils, eosinophils, basophils and natural killer cells.

• Acquired (adaptive or specific) immunity – is not present at birth but is learned. Learning occurs when the immune system of a person encounters invaders and recognises foreign substances (antigens). The components of acquired immunity then learn the best way to attack each antigen and begin to develop a memory for it.

Acquired immunity can take some time to develop after the first exposure, however, afterwards the antigen is remembered, and successive responses will be quicker and more effective. The white blood cells responsible for acquired immunity are lymphocytes (T cells and B cells).

Both mechanisms still use antibodies also known as immunoglobulin, which are proteins produced by white blood cells called B cells. The antibodies tightly bind to the epitope of an invading antigen, tagging the invader for attack or directly neutralising it. An antigen is any substance the immune system can recognise and that can therefore stimulate an immune response.

Antigens can have multiple different epitopes meaning that a number of different antibodies can bind to and attack the same antigen. Polyclonal antibodies are a heterogenous mixture of antibodies with varying antigen binding sites which will bind to varying epitopes of the same antigen.



Monoclonal antibodies are a set of identical antibodies that bind to the same epitope of an antigen. Monoclonal antibodies are produced ex vivo using tissue culture techniques while the polyclonal antibodies are produced in live animals. Monoclonal antibodies provide good batch to batch homogeneity and a reduced probability of cross reactivity to other antigens compared to their polyclonal counterparts (labclinics, 2018).

Antibodies consist of four polypeptides, two heavy chains and two light chains joined to form a “Y” shaped molecule (The University of Arizona, 2000). The amino acid sequence at the tips of the “Y” vary greatly for different antibodies. This is known as the variable region and is made up of between 110-130 amino acids. This variation gives the antibody it’s specificity for binding to different antigens.

The mechanism for destroying antigens is determined by the constant region, which defines which of the five classes an antibody is allocated to – IgM, IgG, Iga, IgD or IgE.

Each antibody is specifically designed to bind to a particular antigen in a lock and key like mechanism. This is the first stage of reactions between antibodies and antigens, of which there are three:

1. Formation of an antigen-antibody complex

2. Visible events such as precipitation and agglutination.

3. The destruction or neutralisation of the antigen.

The different immunoassay test methods are summarised below (Advameg Inc, 2020).

Immunoprecipitation.

The simplest immunoassay method measures the quantity of precipitate, which forms after the reagent antibody (precipitin) has incubated with the sample and reacted with its respective antigen to form an insoluble aggregate. Immunoprecipitation reactions may be qualitative or quantitative.

Particle immunoassays.

By linking several antibodies to the particle, the particle is able to bind many antigen molecules simultaneously. This greatly accelerates the speed of the visible reaction. This allows rapid and sensitive detection of antibodies that are markers of such diseases, as infectious mononucleosis and rheumatoid arthritis.

Immunonephelometry.

The immediate union of antibody and antigen forms immune complexes that are too small to precipitate. However, these complexes scatter incident light and can be measured using an instrument called a nephelometer. The antigen concentration can be determined within minutes of the reaction.

Radioimmunoassay (RIA)

A method employing radioactive isotopes to label either the antigen or antibody. This isotope emits gamma rays, which are usually measured following removal of an unbound (free) radiolabel. The major advantages of RIA, compared with other immunoassays, are higher sensitivity, easy signal detection, and well-established, rapid assays.

The major disadvantages are the health and safety risks posed by the use of radiation and the time and expense associated with maintaining a licensed radiation safety and disposal program. For this reason, RIA has

Antibody Structure (The University of Arizona, 2000)



been largely replaced in routine clinical laboratory practice by enzyme immunoassay.

Enzyme (EIA) immunoassay

This method uses an enzyme to label either the antibody or antigen. The sensitivity of EIA approaches that for RIA, without the danger posed by radioactive isotopes. One of the most widely used EIA methods for detection of infectious diseases is the enzyme-linked immunosorbent assay (ELISA).

Fluorescent immunoassay (FIA)

A method which utilise a fluorescent label or an enzyme label which acts on the substrate to form a fluorescent product. Fluorescent measurements are inherently more sensitive than colorimetric (spectrophotometric) measurements. Therefore, FIA methods have greater analytical sensitivity than EIA methods, which employ absorbance (optical density) measurement techniques.

Chemiluminescent immunoassays

Utilising a chemiluminescent label. Chemiluminescent molecules produce light when they are excited by chemical energy. These emissions are measured by a light detector.

Conduct individual tests, or batches of tests, according to documented methodologies, applying required quality control procedures For all the tests mentioned previously there will be documented methodologies for you to follow. This is to ensure all tests whether carried out individually or as a batch of tests are completed consistently. If different staff members are to carry out the same test they should all follow the same methodology carrying out the test in the exact same way.

This means that all results should be comparable regardless of who completed the analysis and when it was done. A way of further ensuring the reliability of results is the use of a quality control system.

A quality system is formally described as 'the organisational structure, responsibilities, procedures, processes and resources for implementing the management of quality'. Said in a simpler way, a quality system concerns the way an enterprise goes about running its business to achieve its goals. The quality system would usually be documented and is often based around a quality manual that defines and embodies the system.

A very important part of a laboratory’s quality system is quality control.

Quality control (QC) is defined as being “the operational procedures in place to check the quality of products and services”. In effect, these operational procedures include:

• checking a process at appropriate stages to ensure it stays within defined limits (such as to produce the 'right' quality product)

• eliminating the causes of any unsatisfactory performance (reducing the rework and waste that otherwise cost companies money)

• removing or repairing any defective products before they get to the customer.



QC procedures generally involve:

• measurement of a parameter

• the concepts of accuracy and precision regarding that measurement

• a range of acceptance (i.e. the defined limits of quality)

• recording of raw data, calculations and the decision to accept or reject

• recording of QC parameters to follow patterns over time.

Manage tasks and organise work to ensure efficient use of time Planning is vital for completing tasks efficiently and on time as it can reduce any potential work flow issues. These may include being unable to use an instrument as it was already booked, and you failed to check the roster or running out of reagents as you didn’t check and maintain the inventory. This can result in late results or even going beyond holding times.

Some things you could do to aid in being prepared and planned for upcoming work include:

1. List your tasks and rate each according to priority. Then complete the tasks in order of highest priority.

2. Sometimes to ensure efficient use of time it may be necessary to perform tests in batches. When performing tests in batches group samples that have similar testing requirements such as:

o incubation temperature

o additives

o centrifugation

o monitoring - how you monitor samples may be a useful way of grouping them as well. Particularly if samples require the same incubation or other steps to be performed at the same time.

Flag test results that are outside accepted quality control limits The use of quality control data collected throughout testing indicates the accuracy and precision of the test. This data is collected through the use of:

• Blanks – Corrects for the effect of the reagents added and the instrument used

• Standards – Check the accuracy

• Precision Checks (Duplicate Samples) – Check the precision

• Control charts – Identify trends in data

• Alternative methods – Checks the validity of the method.



Blank samples:

A blank sample is created by adding all reagents (chemicals) that we add to our samples and treating the blank sample in the same way that the rest of the samples are treated. This allows us to see what the effects from the reagents and the equipment we use are and to subtract any interferences.

Standards:

Sample(s) of known concentration used to assess the accuracy of an analytical run. Standards covering varying concentrations (low, medium & high) can be used when analysing a range of analyte concentrations in the test samples.

Precision check samples:

A sample containing the analyte at a known concentration (could use a check sample). The same precision check sample is run a number of times (replicates) and the range of values obtained gives an indication of the precision, or repeatability, of the run.

Test results outside accepted quality control limits

Results that are outside quality control limits must be flagged and all affected sample results closely checked. The cause of the non-conforming results must be identified, and it may be necessary to rerun some samples.

Errors in a chemical pathology laboratory come in many forms and can be classified as pre-analysis and post-analysis (Dilworth, et al., 2014). Pre-analysis errors include inappropriate order entry, specimen mis-identification, sorting, aliquoting and pipetting errors. While post-analysis errors may include erroneous data validation, excessive turn-around-time, data entry problems and incorrect interpretation. Corrective action will vary depending upon the error but may involve retesting, further quality controls, seeking assistance or further training.

Store unused sample for possible future reference

Requests for sample retesting may occur such as during legal trials or flagged results. It is therefore imperative that any unused sample is correctly stored so as the integrity of the sample is maintained.

Workplace storage procedures for individual samples must be followed as each sample may require different conditions. For example, some may be stored in the freezer, in the fridge, away from light or away from other samples.

Apply quality control processes to discriminate between significant data and artefact The use of historical trends or control charts can help with the decision as to whether a result outside the norm is correct or if an error has occurred.

Control or run charts are graphs that show the result of testing over time. They are called Control Charts as they are used to ‘control’ (as in quality control) a process. They can be used to make sure that a product or process complies with QA requirements.



The normal situation is for a random arrangement of points on either side of the target. There should be no points outside of the upper or lower target limits – the process or product is said to be within specification. This process is stable with all values near the target – this represents acceptable quality.

When a value does appear outside of the target limits (either above the upper or below the lower limits) you should investigate. This variation is probably a special cause because this is not normal for the system.

This process begins with a normal variation pattern, then with a point outside of the limits. This is not normal for the system. There is probably a special cause such as broken or poorly adjusted equipment. Prompt action has fixed the problem and the system has been brought back within target again.

If you collect data over a period of time you will be able to see what the values usually are when the process is working normally, so you can recognise when it is malfunctioning. If the results are within the normally accepted limits, it is highly probable that they are correct.

If they are outside of the normal limits, you should report the result to your supervisor and investigate the cause. It may be that the result is correctly showing an alteration of the process. It may also be that the process is normal, but there is an error that has been made in testing or recording of the result.

You should also be familiar with possible causes of increased or decreased results such as increased iron results due to oral iron, haemochromatosis or gastrointestinal bleeding. And decreased iron results due to iron deficiency, infection, chronic inflammation.



Confirm with supervisor any further testing requirements If you have had to flag results that are outside the accepted quality control limits it is necessary to determine what has caused the results. It could have been due to either the sample, method or instrument. A testing variation investigation may be necessary, and you should confirm with your supervisor any further testing requirements.

Record all test data, noting any phenomena that may be relevant to the treatment of data or the interpretation of results The word 'data' refers to the results of tests, measurements or analyses. Data is obtained when you calibrate instruments and when you sample or test products. Data can be:

• Quantitative – data are measurements and are written as numbers.

• Qualitative – data are descriptions of samples.

Data must be processed, presented and stored so that it can be found when it is needed. For example, the data obtained from swabbing and plating equipment and surfaces around a plant is recorded and stored. The results can then be compared from time to time to see if there is any change in workplace and product hygiene. If the results showed an increase in bacteria, then urgent action may be required.

If a product or item of equipment fails a test, this must be noted. You should also start the appropriate procedures. For example, if an instrument is calibrated and found not to meet tolerances (acceptable range) and cannot be adjusted, it must be marked as defective and not used until it has been repaired or replaced.

All test data must be recorded even if it is outside specifications. Unusual data can highlight issues with the sample, method or equipment and must be investigated.

It is also important to be aware of causes of increased or decreased results such as artefacts, disease or diets. Ion blood tests can be indicators for specific conditions that a patient may be suffering, for example:

• Increased sodium can be due to water loss through dehydration, diabetes or insipidus. A decreased sodium results can be due to water overload (eg cirrhosis, congestive cardiac failure (CCF), inappropriate antidiuretic hormone secretion (SIADH) or salt loss (e.g. diuretic therapy, adrenal failure, gut or sweat loss, renal impairment).

• Increased potassium could be due to oral overload, cell leakage (sepsis or post-collection), renal disease, acidosis (ketoacidosis, lactic acidosis) or Haemolysis. A decrease could be due to diuretic deficiency, renal tubular disease, steroid excess, gut loss or insulin effect.

• Increased calcium could be due to primary hyperparathyroidism, certain types of cancer, kidney or adrenal gland failure, sarcoidosis and medication or supplements. A decrease could attributed to hypoparathyroidism, kidney failure, pancreatitis, medications and low levels of albumin in the blood, which may indicate malnutrition or liver disease.



Maintain laboratory records


• Record entries on report forms or into a laboratory information management system, accurately calculating, recording or transcribing data as required

• Ensure samples and associated paperwork maintain traceability throughout testing

Record entries on report forms or into a laboratory information management system, accurately calculating, recording or transcribing data as required All results must be recorded and reported, including atypical or unusual results.

All data must be reliably recorded in a way that allows other people to find it and read it later. Results may be recorded straight onto a LIMS, into software such as Excel, onto test sheets or workbooks. All records must be legible and traceable.

Data obtained from dilutions, culturing, sensitivity testing and counting must be recorded with at least the following information:

• Name or ID of the sample, growth conditions and any tests conducted

• The name of the person responsible for the sampling, culturing or testing

• The time and/or date of when the sampling, culturing or testing was done

• The results and any conclusions from analysis, for example, reduced potassium ion concentration indicates effectiveness of treatment

Test results hand written on a result sheet or form should be transcribed into a computer database from which printed reports or statistical charts can be generated. In some large workplaces, where the testing apparatus is linked to a central computer, the results are automatically logged as soon as the measurements are taken.

Accurate transcription of data

If you don’t write down results accurately, mistakes occur, resulting in transcription and transposition errors.

A transcription error occurs when a number from one sheet is incorrectly copied to another sheet or into a computer database program. Typically, a different digit is copied, or a number is written in the wrong space. It is better to write measurements and results directly onto data sheets instead of onto scraps of note-paper during your work.

Examples:

• when 1234 is written as 1254

• wet and dry masses may have been swapped for weighing

• when plate counts are written against the wrong swab samples.



Transposition errors are when the order or position of digits in a number are incorrectly recorded or the decimal point is incorrectly placed.

These errors become a more common fault when working quickly or under pressure. These errors are difficult to spot later because all the same digits are still there.

Examples:

• when 7892 is written as 7982

• when 11.12 is written as 111.2.

To prevent mistakes:

• record measurements on data sheets as soon as possible (for example, take the datasheet to the instrument)

• double-check you have entered the correct figure

• plan work time to attend to reports.

With most of the current complex instrumental techniques the results are automatically entered into the LIMS for their associated sample. The most likely transcription errors involve associating dilution factors with the wrong sample or incorrect sample labelling which could result in loading errors of samples into the autosampler.

Ensure samples and associated paperwork maintain traceability throughout testing Traceability is generally the ability to track a sample from when it is collected, all the treatments and analysis it undergoes and who has carried them out. The requirements of document control and tracking may include:

• Collector/sampler/tester ID

• Test identification

• Date of test

• Number of tests

• Attaching the test request to samples

• Affixing stickers, labels or other code indicators. Any mistakes should not be erased from the test sheet, instead a line should be put through the data with your initial, date and a note as to why it was rejected. This is standard procedure throughout industry. It is important to ensure all equipment that can have an effect on the accuracy or validity of test results is properly calibrated and in good working order.

The traceability system involves both keeping a register of blood products issued in the hospital and recording transfused product details on the patient's file (Victoria State Government, 2008).

Information storage systems must also enable tracking back from the recipient to the donation or batch number and thus back to the laboratory. Laboratory records must therefore be compatible with records of the supplying blood service.



Plasma fractionators and the supplying blood service will also retain records to allow the tracking of any given product or component to the donor and from any donor to the destination of any issued product.

However, where traceability for blood samples differ to standard laboratories is the potential requirement to trace a path between donor and recipient many years after transfusion (Victoria State Government, 2008). This requires hospitals, blood banks and laboratories to retain complete and compatible patient records for many years after they have completed the transfusions.

Legal and ethical responsibilities Ethics are of vital importance in pathology. No new scientific or technological development can claim immunity from ethical scrutiny. More specifically, moral & ethical concerns are of considerable importance in influencing public attitudes towards pathology

The ethical requirements of pathology laboratories are outlined by the Department of Health Standards:

• S1.1 The wellbeing of patients and confidentiality of patient information must be primary considerations in the operation of a pathology service.

• S1.2 The laboratory must have policies and procedures for ensuring the protection of confidential information.

• S1.3 The laboratory must have policies and procedures to ensure that staff treat human samples, tissues or remains with due respect.

Laboratories may have other ethical requirements particular to their organisation, however these are general standards that should be adhered to by all laboratories working in the pathology services.

Professional ethics are the moral bonds that link a profession, the people it serves, and society. The patient’s welfare is paramount in clinical research and healthcare ethics. This includes maintaining privacy and confidentiality with what can be sensitive information.

Unethical behaviours may include, but are not limited to:

• Falsifying results

• Changing recorded dates and times

• Changing sample labels or other documentation such as test request forms.

• Discussing tests and test results with unauthorised people.

All pathology laboratories operating in Australia must meet National Pathology Accreditation Advisory Council (NPAAC) standards to be accredited. NPAAC standards look at required privacy and confidentiality, treating patients with respect, risk management as well as many other aspects.



Environmental sustainability By minimising the generation of waste, you can reduce the likelihood of contamination and accident. You should carefully consider ways in which this can be achieved prior to each process, routine or procedure.

Pipettes, burettes and volumetric flasks that are not contaminated by biological waste should be rinsed with water immediately after use to remove chemical residues. If you do not rinse out the apparatus straight away, the traces of solution that it still contains will dry out and the solute may stick to the glass. This will make it much harder to clean properly later.

Any equipment contaminated with biological waste should be properly treated to ensure all biological material is destroyed before discarding. This may require autoclaving equipment or the use of strong chemicals to ensure all microorganisms have been destroyed.

Laboratory work creates waste and every effort should be made to minimise this waste. Taking blood requires fresh sealed syringes which can generate a deal of plastic waste, sharps waste and biohazard waste. Disposable gloves will be replaced after each use meaning this waste can build up quickly, making the need for efficiency and not having to repeat procedures vital.

It is important to promote efficient waste management and consumption of natural resources by the organisation for environmental sustainability through the following actions:

• The minimisation of waste through implementation of a waste management plan that utilises the waste management hierarchy

• The efficient and effective use of energy and other identified resources (purchasing more efficient freezers and incubators)

• Seeking alternative sources of products so that we use renewable resources where possible

• The efficient use of raw materials minimising waste

• The use of controls to minimise the risk of environmental damage from the use and disposal of hazardous substances

• Efficient water use.

Major sustainability issues that every biological lab face include:

• Energy consumption from fume hoods, freezers, incubators, autoclaves and ovens

• Waste from single use sterile gloves, disposable gowns and masks

• Hazardous chemicals from the strong cleaning products

• Biohazardous waste (bacteria, fungi and cell cultures).



Bibliography

Advameg Inc, 2020. Encyclopedia of surgery. [Online] Available at: https://www.surgeryencyclopedia.com/Fi-La/Immunoassay-Tests.html [Accessed 6 January 2020].

Brooks Life Sciences, 2018. Sample Science Blog. [Online] Available at: https://www.brookslifesciences.com/blog/safe-storage-temperatures-biological-materials [Accessed 19 December 2019].

Centers for Disease Control and Prevention, 2019. What is Spina Bifida. [Online] Available at: https://www.cdc.gov/ncbddd/spinabifida/facts.html [Accessed 19 December 2019].

Davenport, T. U. a. P., 2002. Analysis of general conditions of contract. In: Fundementals of Building Contract Management. s.l.:s.n., p. 229.

Delves, P. J., 2019. Acquired Immunity. [Online] Available at: https://www.msdmanuals.com/en-au/home/immune-disorders/biology-of-the-immune-system/acquired-immunity [Accessed 2 December 2019].

Dilworth, L. L., McGrowder, D. A. & Thompson, R. K., 2014. Identification of Pre-examination Errors in the Chemical Pathology Laboratory at the University Hospital of the West Indies. Indian J Clin Biochem, 29(2), pp. 227-231.

Edwards, S., 2017. Independant Contractors Act 2006. [Online] Available at: http://fairworklegaladvice.com.au/independent-contractors-act-2006/

Felder, R., 2014. Advances in Clinical Laboratory Automation. [Online] Available at: https://www.aacc.org/publications/cln/articles/2014/december/lab-automation.aspx [Accessed 6 January 2020].

Ingraham, P., 2019. You Might Just Be Weird. [Online] Available at: https://www.painscience.com/articles/anatomical-variation.php [Accessed 19 December 2019].

labclinics, 2018. Polyclonal Vs. Monoclonal Antibodies. [Online] Available at: https://www.labclinics.com/en/polyclonal-monoclonal-antibodies/ [Accessed 6 January 2020].

Pūtaiao, T. H., 2019. Chemical Pathology and Medical Laboratory Science. [Online] Available at: https://www.otago.ac.nz/medlabsci/undergraduate/bmedlabsci/chemical-pathology/index.html [Accessed 19 December 2019].

Sica, M., 2012. Ensuring Traceability in a Food Microbiology Laboratory Environment. [Online] Available at: https://nelac-institute.org/docs/meetings/washdc2012/presentations/7DCForum%20Sica.pdf [Accessed 12 December 2019].

Streitberg, G. S., Bwititi, P. T., Angel, L. & Sikaris, K. A., 2009. Automation and Expert Systems in a Core Clinical Chemistry Laboratory. Journal of the Association for Laboratory Automation, 14(2), pp. 94-105.



The University of Arizona, 2000. Antibody Structure. [Online] Available at: http://www.biology.arizona.edu/immunology/tutorials/antibody/structure.html [Accessed 2 December 2019].

Victoria State Government, 2008. Traceability of Transfused Blood and Blood Products. [Online] Available at: https://www2.health.vic.gov.au/about/news-and-events/hospitalcirculars/circ3208 [Accessed 29 November 2019].



Document revision Version Number

Details of the Revision Date Created / Approved

v1.0 Original issue 12/02/2020 JT / JS

v1.1 Legal and ethics edited to correct errors. 19/06/2020 JT

IntroductionProcess samples and associated request formsIdentify specimens and request forms that do not comply with minimum industry requirements for labelling, identification and test requestsRecord any discrepancies and indicate what action is requiredLog samples, recording details that allow accurate tracking and chain of custodyStorage of samples

Perform testsSelect authorised tests indicated for the requested investigationsCommon chemical pathology testsLiver function testsBlood testsGlucose tolerance testDNA testingImmunological tests

Conduct individual tests, or batches of tests, according to documented methodologies, applying required quality control proceduresManage tasks and organise work to ensure efficient use of timeFlag test results that are outside accepted quality control limitsBlank samples:Standards:Precision check samples:Test results outside accepted quality control limitsStore unused sample for possible future reference

Apply quality control processes to discriminate between significant data and artefactConfirm with supervisor any further testing requirementsRecord all test data, noting any phenomena that may be relevant to the treatment of data or the interpretation of results

Maintain laboratory recordsRecord entries on report forms or into a laboratory information management system, accurately calculating, recording or transcribing data as requiredAccurate transcription of data

Ensure samples and associated paperwork maintain traceability throughout testingLegal and ethical responsibilitiesEnvironmental sustainability

BibliographyDocument revision

Date post:	01-Feb-2021
Category:	Documents
Upload:	others
View:	0 times
Download:	0 times

Contents · 2020. 6. 19. · • urinalysis – chemical analysis of urine. ... automation...

Documents