Use of Chemical & Biological Indicators

Dr. Ashraf Abd Elkader El-KelanyGeneral Directorate,

infection Prevention and ControlMOH - KSA

Process Monitoring

Why ?

How often ?

Why Process Monitoring?

Validation is used to check that a product, service, orsystem meets requirements and specifications plusthat it fulfills its intended purpose.

Regular monitoring is necessary to detect anyfailure in the delivery of sterile instrumentsrequired for safe healthcare services.

Do not confuse monitoring with validation.

A sterile product is the result of: The right product The right equipment The right processAll three factors have to be checked.

Why Process Monitoring?

There are 3 fundamental methods ofmonitoring sterilization processes:

Sterilisation Monitoring Concepts

Physical

Chemical

Biological

Sterilization Process Monitoring Devices includePhysical monitors, Chemical Indicators (CIs) andBiological Indicators (BIs).

Each of these devices play a different and specific rolein sterilization process monitoring, and each isessential for sterility assurance.

Sterilisation Process Monitoring Devices

Three legs make a stable stand!

Stability

Physical Monitors

Chemical Indicators(CIs)

Biological Indicators(BIs)

Sterilisation Process Monitoring Devices

There are 3 fundamental methods ofmonitoring sterilization processes:

Sterilisation Monitoring Concepts

Physical

Chemical

Biological

Physical Methods These devices confirm that the specific parameters of

the sterilization cycle have been met. Gauges Continuous measurement of the sterilization

process parameters, e.g., pressure, temperature,and time

Need recalibration Recording devices (e.g., displays, and printouts) Documentation of the measured sterilization

process parameters

Physical Methods Thermometers Measurement of the highest temperature of the

process Easy to use

But no information about when it was reached orfor how long it was maintained

Thermocouples Continuous measurement of temperature Allows continuous recording

There are 3 fundamental methods ofmonitoring sterilization processes:

Sterilisation Monitoring Concepts

Physical

Chemical

Biological

Chemical Indicators (CIs) Reaction depends on achieving one or

more of the critical parameters:(pressure, temperature, humidity, and time)

Result immediately available Always follow the instructions of the

indicator manufacturer regarding storage,expiration date, how to use, cycles it can beused to monitor, and how to interpret results.

Chemical Indicators (CIs)

Class 5 indicator

Class 4 indicator

Chemical Indicators Classes (ISO 11140-1)

Class 1 Process Indicators Class 2 Specific Test Indicators Class 3 Single variable indicators Class 4 Multivariable Indicators Class 5 Integrating Indicators Class 6 Emulating Indicators

Chemical Indicators Classes (ISO 11140-1)

The chemical indicators within each of theseclassifications are further subdivided by thesterilization process for which they are designed to beused.

The classification structure used is only to denote thecharacteristics and intended use of each type ofindicator as defined by the manufacturer. Theclassification has no hierarchical significance.

Your choice should be based on the information youneed to get about a particular sterilization process.

Class 1 - Process IndicatorsUsed for Exposure Control

Designed to react to one or more of the criticalprocess variables

Used to demonstrate that the item has been exposedto the sterilization process & to distinguish processedfrom unprocessed items (Exposure control)

It will show processed result when exposed toconditions which should not occur outside thesterilizer.

The level and uniformity of exposure can not bedetected with such an indicator. No information aboutthe success or failure of the process.

Class 1 - Process IndicatorsUsed for Exposure Control

Practical Application Placement

Outside of package Frequency of Use

Each package unless internal chemical indicator isvisible

Examples of CI class 1Indicator tapes, indicator labels, and load cards

Class 2 - Specific Test IndicatorsUsed for Special Tests

Intended for use in specific test procedures asdefined in relevant sterilizer/sterilization standards

This class is generally a steam penetration airremoval test, commonly known as a Bowie DickTest which is used to evaluate the efficacy of airremoval by vacuum systems (dynamic-air-removal)in pre-vacuum steam sterilizers.Class 2 indicators are used to evaluate the sterilizersperformance (Equipment control).

The original "Huckaback Towel Pack"Dr. J. H. Bowie and Mr. J. Dick

THE BOWIE AND DICK AUTOCLAVE TAPE TEST, The Lancet, (1963), S.586

Class 2 - Specific Test IndicatorsUsed for Special Tests

Practical Application Placement

In empty load, on the bottom shelfover the drain line (coldest spot).

Frequency of Use1) Daily for each pre-vacuum steam sterilizer (first cycle of

the day) after warming up2) Initial installation or relocation of sterilizer, after sterilizer

malfunction, sterilization process failures and majorrepairs (3 consecutive empty loads tested)

Examples of CI class 2Dynamic Air Removal DAR (Bowie-Dick) tests used forequipment control

Dynamic Air Removal DAR test Pack(Bowie-Dick test)

Instructions for use: Unless otherwise directed by the manufacturer the

DAR test should be run in an EMPTY load (nothingelse in the sterilizer) for 3 to 4 minutes cycle withno dry time.

At the end of the cycle, the door should be openedand the cart with the pack removed (the cart shouldnot remain inside the sterilizer to cool down).

After cooling, the pack should be opened and theresults reviewed.

Dynamic Air Removal DAR test Pack(Bowie-Dick test)

Interpretation of the results: A complete and even color change

of the indicator sheet = (PASS). Any incomplete or inconclusive

results = (FAIL), that should beimmediately reported to the CSSDsupervisor and the test repeated.

If the second test fails, do not usethe sterilizer and call maintenanceservices.

Class 3 Single Variable IndicatorsUsed for Pack Control

A single variable indicator is designed to react toone of the critical variables and intended to indicateexposure to a sterilization process at a stated value(SV) of that chosen variable

Indicates exposure inside the pack (Pack Control) toone critical parameter of the sterilization process(single variable in the process e.g. temperature)

If the sterilization process has only one criticalparameter (single variable as irradiation), conclusionscan be made on the result.

Class 3 Single Variable IndicatorsUsed for Pack Control

It may be used as a (Pack Control) monitoring butwould not provide as much information as Class 4,Class 5 or Class 6 Chemical Indicators.

If more than one parameter is required, monitoring asingle parameter is inadequate and must be used inconjunction with other indicating systems.

Class 3 Single Variable IndicatorsUsed for Pack Control

Practical Application Placement

Inside package Frequency of Use

Inside each package in the areas considered thegreatest challenge for sterilant penetration.

Examples of CI class 3Temperature tube that contains a chemical pellet thatmelts at a specific temperature (SV).

Class 3 Single Variable Indicators

Designed for one criticalparameter

Stated value for that singlevariable

Temperature tubes Melt and change color if

reach stated temperature,e.g., 134C.

Class 4 Multivariable IndicatorsUsed for Pack Control

A multi-variable indicator is designed to react to twoor more of the critical variables and intended toindicate exposure to a sterilization cycle at statedvalues (SVs) of the chosen variables.

Indicates exposure inside the pack (Pack Control) totwo or more critical parameters of the sterilizationprocess (multivariable, e.g. temperature & time)

They may need to be used in combination with otherindicating systems to allow proper interpretation ofthe process.

Class 4 Multivariable IndicatorsUsed for Pack Control

Practical Application Placement

Inside package Frequency of Use

Inside each package in the areas considered thegreatest challenge for sterilant penetration.

Examples of CI class 4Multi-variable CI is used for pack control.These internal Chemical Indicators are usually paperstrips printed with a Chemical Indicator ink.

Integrating indicators is designed to react to allcritical variables.The SVs are generated to be equivalent to, or exceedthe performance requirements given in the ISO 11138series for Biological Indicators .

They must therefore respond to effectivecombinations of all critical parameters.

Similar to biological indicators, slight changes in oneparameter may be compensated by changes in anotherparameter (e.g. slightly lower temperaturecompensated by longer exposure to saturated steam).

Class 5 Integrating IndicatorsUsed for Pack & Load Control

Class 5 Integrating Indicator is designed to mimicthe behaviour of biological indicator, frequentlyreferred to as A chemical Biological.

However they do not replace the BI, the release ofloads is still based on the result of BI, in emergencycases we can release the load based on Class 5Indicator but this doesnt include implants.

For this additional monitoring the Class 5 IntegratingIndicator must be used in the appropriate challengetest pack or Process Challenge Device (PCD).

Class 5 Integrating IndicatorsUsed for Pack & Load Control

Class 5 Integrating Indicators

Response must correlate to a BI atthree time/temperature relationships 121C/250F 135C/276F and a temperature in between such as

128C/263F Cannot be a Class 5 CI unless have 3

stated values listed on the product orinserted in the package.

Class 5 Integrating IndicatorsUsed for Pack & Load Control

Chemical Emulating Indicators can be used only toshow that all the critical variables of sterilizationprocess have been achieved for a specificsterilization cycles for which they are labeled, e.g.,Dual Temperature 121c / 12 minutes - 134c / 4minutes).

Class 6 Emulating IndicatorsUsed for Pack & Load Control

Class 5 - Integrating Indicators VersusClass 6 - Emulating Indicators

An integrator is designed tobe accurately correlated to abiological indicator.

One indicator for all steamcycles

If the combinations of thecycle critical parameters (atthe three time / temperaturerelationships) are notachieved, class 5 integratorfails.

An Emulator is designed toshow that a sterilizer workedaccording to its settings

We can not correlate theperformance of an emulatorfor a special test cycle to allcycles used.

If the sterilizer cycle settings(time / temperature) do notmatch exactly the SVsindicated on the emulatingindicator it fails.

Class 5 - Integrator Class 6 - Emulator

Class 5 - Integrating Indicators& Class 6 - Emulating Indicators

Frequency of use: Chemical Indicators must be routinely used within

each package, tray, or containment device (rigidcontainer, cassette, or organizing tray) to besterilized.

A Chemical Indicator challenge test pack or ProcessChallenge Device PCD (containing a Class 6 or aClass 5 chemical Indicator) may be routinely used forassurance of the adequacy of the sterilization cyclewith all loads containing non-implantable items(Load Control).

Class 5 - Integrating Indicators& Class 6 - Emulating Indicators

Placement: Chemical Indicators must be placed in the area of the

package, tray, or containment device considered to beleast accessible to steam penetration (spot of greatestchallenge).

For containment device, follow the manufacture'swritten instructions for placement of the ChemicalIndicator.

Process Monitoring How Often? With What?

Equipment Control Every day Bowie Dick Test

Sterilization Monitoring in 5 Steps

Load Control Every load BIs / CIs Test Packs (PCD)

Exposure Control Every pack Tape, Strips, Labels

Pack Control Every pack Chemical Indicators

Record Keeping Every action Labels, Record books

Clean Prep/Pack Sterilize Store Issue/Use

Monitored by load and exposure control

Monitored by exposureand pack control

There are 3 fundamental methods ofmonitoring sterilization processes:

Sterilisation Monitoring Concepts

Physical

Chemical

Biological

Biological Indicators

Biological indicator Test system containing viable micro-organisms

providing a defined resistance to a specificsterilization process.

Biological Indicators

How they work . . . Spores are exposed to the sterilization

process along with items beingsterilized

After processing, the exposed sporesare immersed in an optimized recoverymedia and incubated at optimaltemperature.

Spore viability indicates a process failureGolden standard is 7 days of incubation*

Attest Rapid Readout DesignCap

Filter filters out contaminates

Media Ampule Nutrients, enzymesubstrate and pH indicator

Barrier Material Concentratesfluorescent productSpore strip Paper coated with spores

Vial

Attest Model 290Auto-reader/Incubator

The system includes anincubator (that can beprogrammed for 37 or 60 C)and fluorescence detector.

Automatic calibration andtiming for each vail as it isplaced in the reader.

Positives (Red light with anaudible Alarm) indicated afterthe 3rd reading.

Negatives (Green light) at theend of incubation time

Instructions forBiological Indicators use

Always follow the Biological Indicator manufacturer's instructions for storage, expiration date, how to use, how to incubate (follow-up) after sterilization, and how to interpret results.

Biological Indicatorsfor Steam Sterilizers (Autoclaves)

Frequency of use: A Biological Indicator challenge test pack (containing

Biological Indicator Chemical Indicator [Class 5 orClass 6]) should be used at least weekly; preferablydaily: for routine release of loads containing non-implantable items.

After steam sterilizer installation, relocation,malfunction, major repairs, and after sterilizationprocess failures. Each sterilization cycle type usedshould be tested (gravity displacement, pre-vacuum, orflash cycles).

Biological Indicatorsfor Steam Sterilizers (Autoclaves)

Frequency of use (con.): A Biological Indicator challenge test pack (containing

Biological Indicator + Chemical Indicator [Class 5 orClass 6]) should be used with for release of each loadcontaining implantable devices.

All implantable devices should be quarantined untilBiological Indicators results are available.

When running a gravity displacement cycle(Biological Indicator test pack must be included inthe load since this cycle is not routinely tested)

Biological Indicatorsfor Steam Sterilizers (Autoclaves)

Timing: In the first working load of the day after Dynamic Air

Removal test - DAR (Bowie-Dick test)Placement: Biological Indicator challenge test pack must be

placed in a fully loaded chamber, in the area of thesterilizer chamber and load that is least favorable forsterilization (coldest spot).It should be identified by the manufacturer, usually inthe front, bottom section near the drain line.

Biological Indicatorsfor Steam Sterilizers (Autoclaves)

Activation & Incubation: Unless there are special recommendations by the

manufacturer for incubation, "rapid readout" BI testproviding a final result for steam sterilization cyclesin three hours (wrapped loads) and one hour for flashcycles (unwrapped load).

Control: Control Biological Indicator vial is needed to verify

the pre-sterilization viability of the spores. The test Biological Indicator vial must be of the same

lot number as the control Biological Indicator vialotherwise the test is considered not valid.

Biological IndicatorsInterpretation of Results

Biological Indicator

Test Vial

Biological Indicator

Control Vial

Dead Spores Viable Spores

Viable Spores Viable Spores

Dead Spores Dead Spores

Dead Spores Not Used

Sterilization Process Success

Sterilization Process Failure

Biological Indicators Failure

Invalid Test

Biological Indicatorsfor Gas Plasma Sterilizers

Frequency of use: BIs for Low Temperature Gas Plasma sterilizer must

be used daily.Timing: In the first load of the day.Placement: Biological Indicator test pack must be placed on the

bottom shelf, back of gas plasma sterilizer (spot ofgreatest challenge).

Biological Indicatorsfor Gas Plasma Sterilizers

Activation & Incubation: Unless there are special recommendations by the

manufacturer for incubation, the Biological Indicatorsfor gas plasma need 24 (or 48) hours to get a finalreading.

Control: Control Biological Indicator vial is needed to verify

the pre-sterilization viability of the spores. The test Biological Indicator vial must be of the same

lot number as the control Biological Indicator vialotherwise the test is considered not valid.

Biological Indicatorsfor Ethylene Oxide gas (EtO) Sterilizers

Frequency of use: Biological Indicators for (EtO) Ethylene Oxide gas

must be used with each load/cycle.Placement: Biological Indicator test pack must be placed in the

area of greatest challenge (least favorable forsterilization). The EtO sterilizer manufacturer shouldidentify the exact location of this area, usually thecenter of the load.

Biological Indicatorsfor Ethylene Oxide gas (EtO) Sterilizers

Activation & Incubation: Unless there are special recommendations by the

manufacturer for incubation, the Biological Indicatorsfor EtO need 48 hours to get a final reading.

Control: Control Biological Indicator vial is needed to verify

the pre-sterilization viability of the spores. The test Biological Indicator vial must be of the same

lot number as the control Biological Indicator vialotherwise the test is considered not valid.

physical + chemical + biological monitoring +

documentation of the results

Good, meaningful control

Safe sterilization process

Final Conclusion

Any questions left?