INTRODUCTION TO CLINICAL BIOCHEMISTRY
DR. MD. MAHBUBUR RAHMAN MBBS, M. Phil MSc. (Biotechnology)
DEPT. OF BIOCHEMISTRY
RAJSHAHI MEDICAL COLLEGE
After the end of the session student will able to know the
• Definition of Clinical Biochemistry
• Core and Emergency Biochemical Test
• Colorimeters and its principle
• Electrophoresis technique
• Characteristics of Good laboratory
Definition of Clinical Biochemistry
Is that branch of laboratory medicine in which
Chemical and Biochemical methods are
applied to study the disease.
Use of Biochemical Test
• To diagnosis the disease
• To monitoring the treatment
• Screening for disease
• In assessing the prognosis of disease
Core Biochemistry
• Most the Biochemistry laboratories provide the
commonly requested test which are of value of
many patient is known as Core Biochemical test.
Core Biochemical test are:
• Sodium, Potassium,Chloride& Bicarbonate
• Urea and Creatinine
• Calcium and Phosphate
• Total protein and Albumin
• Bilirubin and alkaline Phosphatase
• Alanine aminotransferase (ALT) & Aspartate
Aminotransferase (ALT)
• Thyroxin & TSH
• ɣ GT ( Gamma glutamyl transpeptidase)
• Creatin kinase
• Glucose and amylase
Core Biochemistry
Emergency Test
• Urea and Electrolytes
• Blood Gases
• Amylase
• Glucose
• Salicylates
• Paracetamol
• Calcium
Specialised Test
• Hormones
• Specific Proteins
• Trace elements
• Vitamins
• Drugs
• Lipids and Lipoproteins
• DNA analysis
PHOTOMETRY
• Is the study of measurement of light.
• Spectrophotometry is defined as the measurement
of the intensity of light at selected wavelength
Beer’s Law
States that the concentration of substances is
directly proportional to the amount of light
absorbed or inversely proportional to the
logarithm of transmitted light. This law
expressed as
A= abc
Where A indicate Absorbance, a indicate
proportionality constant defined as
absorptivity, b indicate light path in cm, c
indicate concentration of absorbing compound
usually expressed in gm per litre.
Beer’s Law
Lambert’s Law
When a monochromatic light is passing through a
solution, the intensity of light transmitted decreases
exponentially with increasing path length.
Absorbance
The amount of light absorbed by the color of
solution is known as absorbance.
Instrument use to read absorbance
• Filter photometer / Colorimeter (Use filter)
• Sprectrophotometer ( Use prism or grattings)
–Single beam sprectophotometer
–Double beam sprectophotometer
Colorimeter
Is the instrument that is used to measure color of a
solution.
or
Is used to measure the concentration of a substance in
a patient’s sample by comparing the amount of light it
absorbs with that absorbed by a standard preparation
that contains a known amount of the substances being
tested.
Component of colorimeter
• A light source
• A means to isolate light of desired
wavelength ( filter or monochromator)
• Fiber optic
• Cuvet
• A photodetector
• A reader device
• A microprocessor
Component
light entrance Filter Exit Cuvet Detector Meter
source slit slit
Difference between colorimeter and spectrophometer
Colorimeter Spectrophometer
Use filter Use prism or grattings
Only visible light can be measured
Beyond the visible light can be measured
Result is less accurate Result is more accurate
Calculation
Concentration of test
=Absorbance of test
Absorbance of standard X Concentration of Standard
Test done By colorimeter
• Blood glucose
• Serum Creatinine
• Serum Cholesterol
• Serum TG
• Serum Bilirubin
• ALT & AST
Sample used in Biochemistry
• Blood
• Urine
• Feces
• Spinal fluid
• Synovial fluid
• Amniotic fluid ( Amniocentesis)
• Pleural /Pericardial and ascitic fluid
• Saliva
• Swabs
• Solid Tissue: Malignant tissue from breast for
estrogen and progesteron
• Hair and finger nail: have been used to detect
trace metal.
Sample used in Biochemistry
Electrophoresis
Is a comprehensive term that refers to the
migration of charged solutes or particle of any
size in a liquid media under the influence of
electric field.
Types of Electrophoresis
• Slab gel Electrophoresis
• Disc Electrophoresis
• Isoelectric Electrophoresis
• Isotachophoresis
• Pulse field Electrophoresis
• Two dimensional Electrophoresis
• Capillary Electrophoresis
• Microchip Electrophoresis
DEFINITION OF ACCURACY
Accuracy is defined as closeness of agreement between
the test result and the accepted true value.
Accuracy defines how close the measured value is to
the actual value
DEFINITION OF ACCURACY
Agreement between the best estimate of a quantity
and its true value.
DEFINITION OF PRECISION
• Precision is the reproducibility of analytical method.
• Precision is a measure of reproducibility.
• Agreement between replicate measurement.
DEFINITION OF SENSITIVITY
• Sensitivity of an assay is measure how little analyte
that can detect by the assay.
• Sensitivity of an assay is measure that can able to
detect the lowest amount of the analyte by the assay.
• The ability of an analytical method to detect the small
quantities of the measured component
SPECIFICITY
• Specificity of an assay relates how good the assay is
at discriminating between the requested analytes
and surrounding interfering substances.
• The ability of an analytical method to determine
solely the components it purports to measure.
QUALITY ASSURANCE
QA has been summerised as the :
Right result, at the
Right time, on the
Right specimen, from the
Right patient with result interpretation based on
correct reference data, and at the
Right price.
QUALITY CONTROL
• The term quality control covers that part quality
assurance which primarily concerns the control of
errors in the performance of test and performance
of test results.
SI unit
The International system of unit has been
developed and agreed internationally in 1960.
.
It overcomes language barriers, enabling an
exchange of health information within a
country and between nations to be made
without the misunderstanding which arise
when each country or even a separate hospital
within a country uses its own units of
measurement for reporting tests
SI unit
CLASSIFICATION OF SI UNIT
• SI BASE UNIT
• SI DERIVED UNIT
• SI PREFIXES
SI BASE UNIT
The international system of Units is based on the
meter-kilogram- Second system and replaces both
the foot-pound-second system and centimeter-
gram-second system.
SI BASE UNIT
SI base unit Symbol Quantity measure
Meter m Length
Kilogram Kg Mass
Second S Time
Mole Mol Amount of substance
Ampere A Electric current
Kelvin K Temperature
Candela Cd Luminous intensity
SI DERIVED UNIT
SI derived unit Symbol Quantity measure
Square meter m2 Area
Cubic meter m3 Volume
Meter per second m/s Speed
• SI derived units consist of combinations of base units.
SI PREFIXES
• To enable the measurement of quantities larger or
smaller than the base units or derived units the SI
unit system also includes a set of prefix a unit
larger or smaller.
• example: micro, nano, pico femto
Conversion of conventional unit to SI unit
mg/dl x 10
mmol/L =
Molecular wt of substances
Molecular wt
Glucose --—180
Creatinine ----113
Cholesterol--- 386
Bilirubin ----- 584
Urea-----------60
Different SI unit
• SI unit of
– Glucose – mmol/ L
– Urea--- mol/ L
– Creatinine-- µ mol/L
– Bilirubin ---µ mol/L
– Albumin gm/L
»Thank You