ASTM E1766-95(2002)

Standard Test Method for Determination of Effectiveness of Sterilization Processes for Reusable Medical Devices

SIGNIFICANCE AND USE
The test method is designed to demonstrate that all accessible surfaces and internal recesses or lumina of previously cleaned, reusable medical devices can be rendered free of recoverable microorganisms when processed in a specified sterilizer cycle.
Surviving spores are recovered by swabbing, brushing, or irrigating with an elution fluid. Recovery methods may be enhanced by mechanical action, sonication, and repeated flushing with elution fluid.
Note 1—The spore inoculation technique described in this test method is only one of the available procedures for testing the sterilization of devices. Spores on paper strips (biological indocators) are a traditional tool used to develop and monitor sterilization cycles and are also appropriate for the evaluation of sterilization of medical devices.6
SCOPE
1.1 This test method covers a reproducible procedure for testing processes used to sterilize reusable medical devices (instruments). This test method is not designed to validate a sterilization process, but tests an established sterilization cycle or process. It is a practical test of the effectiveness of a sterilization process applied to reusable medical devices. Bacterial spores more resistant to the test sterilant than the natural bioburden of the instrument are used as the test organisms. Commercially available liquid suspensions of bacterial spores are used to inoculate the instruments.
1.2 This test method is intended for reusable medical devices cleaned in accordance with the device manufacturer's instructions and prepared for sterilization in accordance with the instructions for the sterilization process being used.
1.3 This test method assumes that cleaned, reusable medical devices will be free of visible soil but may have remaining adherent bioburden. A worst-case bioburden can be represented by suspensions of bacterial endospores, which are commercially available for monitoring chemical or physical sterilization processes. These endospores should have a verifiable resistance (D value) to the specific process and sterilant being evaluated.
1.4 It is impractical to test for the sterility of some devices by immersion in growth medium because of their complexity, size, and availability (for long-term incubation) or adverse effects on the devices from long-term immersion. Therefore, elution, rinsing, or swabbing techniques are used to recover test organisms from inoculated devices.
1.5 A recovery control will be included by inoculation of a test device and use of the elution methods without applying the sterilization process being tested. A minimal recovery of 106 colony-forming unit (CFU)/mL per device is required for the recovery control.
1.6 Results of the recovery control and process test cycle are compared to determine the effectiveness of the sterilization process.
1.7 Results of the recovery control and applied inoculum are compared to determine the recovery efficiency, if desired.
1.8 The procedure should reveal that tested devices are free of recoverable microorganisms when five or more consecutive tests are conducted.
1.9 A knowledge of microbiological techniques is required to conduct these procedures.
1.10 The values stated in SI units are to be regarded as the standard.
1.11 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 09-Oct-2002
• ICS: 11.080.10 - Sterilizing equipment
• Technical Committee: E35 - Pesticides, Antimicrobials, and Alternative Control Agents
• Drafting Committee: E35.15 - Antimicrobial Agents

Relations

• Replaces: ASTM E1766-95 - Standard Test Method for Determination of Effectiveness of Sterilization Processes for Reusable Medical Devices
• Effective Date: 10-Oct-2002
• Replaced By: ASTM E1766-95(2007) - Standard Test Method for Determination of Effectiveness of Sterilization Processes for Reusable Medical Devices
• Effective Date: 01-Nov-2007
• Referred By: ASTM F3127-22 - Standard Guide for Validating Cleaning Processes Used During the Manufacture of Medical Devices
• Effective Date: 10-Oct-2002

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:E1766–95 (Reapproved 2002)
Standard Test Method for
Determination of Effectiveness of Sterilization Processes for
Reusable Medical Devices
This standard is issued under the fixed designation E 1766; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 1.6 Resultsoftherecoverycontrolandprocesstestcycleare
compared to determine the effectiveness of the sterilization
1.1 This test method covers a reproducible procedure for
process.
testing processes used to sterilize reusable medical devices
1.7 Resultsoftherecoverycontrolandappliedinoculumare
(instruments). This test method is not designed to validate a
compared to determine the recovery efficiency, if desired.
sterilization process, but tests an established sterilization cycle
1.8 The procedure should reveal that tested devices are free
or process. It is a practical test of the effectiveness of a
of recoverable microorganisms when five or more consecutive
sterilization process applied to reusable medical devices. Bac-
tests are conducted.
terial spores more resistant to the test sterilant than the natural
1.9 A knowledge of microbiological techniques is required
bioburden of the instrument are used as the test organisms.
to conduct these procedures.
Commercially available liquid suspensions of bacterial spores
1.10 The values stated in SI units are to be regarded as the
are used to inoculate the instruments.
standard.
1.2 This test method is intended for reusable medical
1.11 This standard does not purport to address all of the
devices cleaned in accordance with the device manufacturer’s
safety concerns, if any, associated with its use. It is the
instructions and prepared for sterilization in accordance with
responsibility of the user of this standard to establish appro-
the instructions for the sterilization process being used.
priate safety and health practices and determine the applica-
1.3 This test method assumes that cleaned, reusable medical
bility of regulatory limitations prior to use.
devices will be free of visible soil but may have remaining
adherentbioburden.Aworst-casebioburdencanberepresented
2. Referenced Documents
by suspensions of bacterial endospores, which are commer-
2.1 ASTM Standards:
cially available for monitoring chemical or physical steriliza-
D 1193 Specification for Reagent Water
tion processes. These endospores should have a verifiable
E 1054 Practices for Evaluating Inactivators of Antimicro-
resistance (D value) to the specific process and sterilant being
2 bial Agents Used in Disinfectant, Sanitizer, Antiseptic, or
evaluated.
Preserved Products
1.4 It is impractical to test for the sterility of some devices
by immersion in growth medium because of their complexity,
3. Terminology
size, and availability (for long-term incubation) or adverse
3.1 Definitions:
effects on the devices from long-term immersion. Therefore,
3.1.1 bioburden—the number and types of viable microor-
elution,rinsing,orswabbingtechniquesareusedtorecovertest
ganisms that contaminate a device.
organisms from inoculated devices.
3.1.2 CFU—colony-forming unit.
1.5 A recovery control will be included by inoculation of a
3.1.3 inoculum—the number (usually specified as CFUs)
test device and use of the elution methods without applying the
and type (genus and species) of viable microorganisms used to
sterilization process being tested. A minimal recovery of 10
contaminate a given sample or device.
colony-forming unit (CFU)/mL per device is required for the
3.1.4 sporicidal agent—any chemical or physical agent that
recovery control.
kills spores.
3.1.5 sterilant—any sterilizing agent.
This test method is under the jurisdiction of ASTM Committee E35 on
Pesticides and Alternative Control Agents and is the direct responsibility of
Subcommittee E35.15 on Antimicrobial Agents.
Current edition approved October 10, 2002. Published March 2003. Originally For referenced ASTM standards, visit the ASTM website, www.astm.org, or
approved in 1995. Last previous edition approved in 1995 as E 1766 - 95. contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
Oxborrow, G. S., and Berube, R., “SterilityTesting—Validation of Sterilization
Processes, and Sporicide Testing,” Disinfection, Sterilization, and Preservation, the ASTM website.
Block, S. S., 4th Edition, Lea and Febiger, Philadelphia, PA, 1991, pp. 1047–1058. Withdrawn.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
E1766–95 (2002)
3.1.6 sterile—a state of being free of living organisms. 5.2 Surviving spores are recovered by swabbing, brushing,
3.1.7 sterilization cycle or process—a physical or chemical or irrigating with an elution fluid. Recovery methods may be
process that has been demonstrated to meet applicable criteria enhanced by mechanical action, sonication, and repeated
for sterilization as defined by AAMI. flushing with elution fluid.
3.1.8 sterilizer—any device using a chemical or physical
NOTE 1—The spore inoculation technique described in this test method
process that produces sterile materials.
is only one of the available procedures for testing the sterilization of
3.2 Definitions of Terms Specific to This Standard:
devices. Spores on paper strips (biological indocators) are a traditional
3.2.1 applied inoculum—the estimated count of the suspen- tool used to develop and monitor sterilization cycles and are also
appropriate for the evaluation of sterilization of medical devices.
sionofbacterialsporesexpressedasCFU/mLusedtoinoculate
the test devices. This value may be used if the efficiencies of
6. Apparatus
the recovery methods are determined.
6.1 Syringes, 10 to 50 mL, sterile.
3.2.2 process test cycle—a complete sterilization cycle that
6.2 Sterile Cotton Swabs.
uses all parameters of the sterilization process as dictated by
6.3 Sterile Petri Dishes.
the manufacturer.
6.4 Sterile Test Tubes, to hold 10 mL.
3.2.3 recovery control—the CFU recoverable from a device
6.5 Sterile Glass Bottles, to hold 50 mL.
following inoculation and optional drying of the spore suspen-
6.6 Steam Sterilizer.
sion in or on the unprocessed device. The recovery of$10
6.7 Water Bath,48 6 2°C.
CFUs per device is required.
6.8 Incubator(s),35 6 2°C and 55 6 2°C.
3.2.4 recovery effıciency—a measure of the recovery of
6.9 Colony Counter.
inoculated organisms from a device may be determined when
6.10 Medical Device, precleaned in accordance with the
necessary. The recovery efficiency may be expressed as the
manufacturer’s instructions.
ratio of the CFU from the recovery control compared to the
6.11 Disposable or Reusable Membrane Filter Apparatus,
CFU of the applied inoculum. This value is multiplied by 100
sterile, 0.45-µm pore size.
to express efficiency as a percent. It is recommended that a
6.12 Micropipette, calibrated to dispense 5 to 20 µL.
minimumofthreetestsbeperformedwhenestimatingrecovery
6.13 Other devices or apparatus specified by the sterilant,
efficiency.
medical device, or sterilizer manufacturer.
3.2.5 reusable medical devices—any medical device that is
claimed to be usable after reprocessing.
7. Reagents
3.2.6 spore—a bacterial endospore. (Strain identification
and the means used to identify whether the vegetative or spore 7.1 Purity of Reagents—Reagent grade chemicals shall be
state is present should be indicated.) used in all tests. Unless otherwise indicated, it is intended that
3.2.7 worst-case—the intentional exaggeration of one or all reagents conform to the specifications of the Committee on
more parameters of a test compared to normal clinical condi- Analytical Reagents of the American Chemical Society where
tions. such specifications are available. Other grades may be used,
provided it is first ascertained that the reagent is of sufficiently
4. Summary of Test Method high purity to permit its use without lessening the accuracy of
the determination.
4.1 Percent recovery of inoculum may be used to ensure
7.2 Purity of Water—Unless otherwise indicated, references
reproducible inoculation and recovery techniques.
to water shall be understood to mean reagent water as defined
4.2 The test method is performed by contaminating the
by Type III of Specification D 1193.
cleaned reusable medical device with a bacterial endospore
7.3 Media:
suspension.
7.3.1 Type III or Better ASTM Water, for making broths and
4.3 After inoculation, and drying, if required, the device is
elution fluids.
prepared and processed according to the sterilant or sterilizer
7.3.2 Sterile USP Fluid D —(elution fluid), containing
manufacturer’s instructions.
polysorbate80orstrippingsolution containing0.4gKH PO ,
4.4 Following the sterilization process, the test devices are 2 4
10.1 g Na HPO , and 1.0 g.
sampled using specified elution techniques to recover any 2 4
surviving spores.
5. Significance and Use
United States Pharmacopeia, XXIII, Rand McNally, Taunton, MA, 1995, pp.
200–206.
5.1 The test method is designed to demonstrate that all
Reagent Chemicals, American Chemical Society Specifications, American
accessible surfaces and internal recesses or lumina of previ-
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
ouslycleaned,reusablemedicaldevicescanberenderedfreeof
listed by the American Chemical Society, see Analar Standards for Laboratory
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
recoverable microorganisms when processed in a specified
and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,
sterilizer cycle.
MD.
United States Pharmacopeia, XXII, “Sterility Tests, Diluting and Rinsing
Fluids,” Rand McNally, Taunton, MA, 1990, p. 1484.
Williamson, P., “Quantitative Estimation of Cutaneous Bacteria,” Skin Bacteria
See “Guideline for Industrial Ethylene Oxide Sterilization of Medical Devices” and Their Role in Infection, Marbac, H. I., and Hildick-Smith, G., eds., McGraw-
(ST27), AAMI, Arlington, VA, 1992, for typical criteria. Hill, New York, NY, 1965.
E1766–95 (2002)
7.3.3 Isooctylphenoxypolyethoxy Ethanol (Triton X-100), test tube or other sterile container. Alternatively, recovery can
in 1-L distill
...