ASTM D4196-05(2019)

Standard Test Method for Confirming the Sterility of Membrane Filters

SIGNIFICANCE AND USE
5.1 This test method may be employed to check the sterility of commercially procured sterile membrane filters. The test also confirms that sterilized filters have not been contaminated. Additionally, this test may be used to monitor the efficacy of in-house sterilization procedures. Filter packages that have obvious packaging defects should not be tested because sterility may have been compromised.
SCOPE
1.1 This test method describes a test to confirm the sterility of either manufacturer presterilized or user-sterilized analytical membrane filters.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Oct-2019
• ICS: 11.080.99 - Other standards related to sterilization and disinfection
• Technical Committee: D19 - Water
• Drafting Committee: D19.08 - Membranes and Ion Exchange Materials

Relations

• Replaces: ASTM D4196-05(2011) - Standard Test Method for Confirming the Sterility of Membrane Filters
• Effective Date: 01-Nov-2019
• Refers: ASTM D1129-13(2020)e2 - Standard Terminology Relating to Water
• Effective Date: 01-May-2020
• Refers: ASTM D1129-10 - Standard Terminology Relating to Water
• Effective Date: 01-Mar-2010
• Refers: ASTM D1129-06ae1 - Standard Terminology Relating to Water
• Effective Date: 01-Sep-2006
• Refers: ASTM D1129-06a - Standard Terminology Relating to Water
• Effective Date: 01-Sep-2006
• Refers: ASTM D1193-06 - Standard Specification for Reagent Water
• Effective Date: 01-Mar-2006
• Refers: ASTM D1129-06 - Standard Terminology Relating to Water
• Effective Date: 15-Feb-2006
• Refers: ASTM D1129-04e1 - Standard Terminology Relating to Water
• Effective Date: 01-Mar-2004
• Refers: ASTM D1129-04 - Standard Terminology Relating to Water
• Effective Date: 01-Mar-2004
• Refers: ASTM D1129-03a - Standard Terminology Relating to Water
• Effective Date: 10-Aug-2003
• Refers: ASTM D1129-03 - Standard Terminology Relating to Water
• Effective Date: 10-Mar-2003
• Refers: ASTM D1129-02a - Standard Terminology Relating to Water
• Effective Date: 10-Jul-2002
• Refers: ASTM D1129-01 - Standard Terminology Relating to Water
• Effective Date: 10-Jul-2002
• Refers: ASTM D1129-02 - Standard Terminology Relating to Water
• Effective Date: 10-Feb-2002
• Refers: ASTM D1129-99a - Standard Terminology Relating to Water
• Effective Date: 10-Feb-2002

Overview

ASTM D4196-05(2019): Standard Test Method for Confirming the Sterility of Membrane Filters establishes a systematic approach for verifying the sterility of analytical membrane filters, whether they are presterilized by the manufacturer or subsequently sterilized by the user. This international standard, developed by ASTM International, outlines reliable testing procedures critical for quality assurance in laboratories, pharmaceutical manufacturing, and water analysis. Ensuring that membrane filters remain sterile is essential for preventing contamination in sensitive analytical and microbiological applications.

Key Topics

• Sterility Verification: The method determines whether commercially supplied or in-house sterilized membrane filters maintain sterility before use.
• Test Procedure: Membrane filters are immersed in sterile culture media, then incubated at temperatures conducive for microbial growth. Any microbial growth observed indicates contamination or sterility failure.
• Media and Conditions: Uses fluid thioglycollate and soybean-casein digest media, incubated under specified temperature and time conditions to detect bacteria, fungi, and yeasts.
• Retest Protocols: If initial tests show microbial growth, defined retest procedures using additional filter samples are applied to confirm results.
• Safety and Compliance: Laboratories using this standard are responsible for implementing appropriate safety, health, and environmental controls, and assessing regulatory requirements as applicable.

Applications

The test method outlined in ASTM D4196-05(2019) is valuable across several domains where the sterility of membrane filters is critical:

• Laboratory Quality Control: Used to confirm the sterility of membrane filters prior to their use in microbiological and analytical laboratory work.
• Pharmaceutical Industry: Employed in monitoring and verifying the effectiveness of sterilization procedures for membrane filters used in sterile drug production or quality control testing.
• Water and Environmental Testing: Essential for ensuring that filters used in water analysis are free from contamination, which is vital for obtaining accurate results in environmental compliance monitoring.
• Medical and Biotechnology Sectors: Critical for maintaining aseptic conditions in diagnostic testing, research, and production processes requiring sterile filtration components.

Related Standards

• ASTM D1193 - Specification for Reagent Water: Defines the quality requirements for laboratory water used in preparing media and solutions during sterility testing.
• ASTM D1129 - Terminology Relating to Water: Provides terminology supporting the understanding and consistent application of water-related test standards.
• United States Pharmacopeia (USP) Sections on Sterilization and Sterility Testing: Offers additional guidance and requirements pertinent to sterility testing procedures in pharmaceutical applications.

Practical Value

By following ASTM D4196-05(2019), organizations ensure robust sterility testing of membrane filters, reduce the risk of contamination in sensitive testing and production environments, and maintain compliance with international quality standards. The protocol’s focus on both commercially procured and in-house sterilized filters, along with its structured retest strategy, delivers a high level of quality assurance for laboratories and manufacturers operating in regulated environments.

Keywords

membrane filter sterility, sterility test method, ASTM D4196, quality control, sterile filtration, laboratory best practice, reagent water, contamination prevention, sterility compliance, microbiological sterility testing

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D4196 −05 (Reapproved 2019)
Standard Test Method for
Confirming the Sterility of Membrane Filters
This standard is issued under the fixed designation D4196; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope 4. Summary of Test Method
1.1 This test method describes a test to confirm the sterility 4.1 The membrane filters are immersed in sterile culture
media and incubated at temperatures that are suitable for
of either manufacturer presterilized or user-sterilized analytical
membrane filters. growth of viable bacteria, fungi, and yeasts. Growth of
organisms is evidence that the filter has failed the test.
1.2 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this
5. Significance and Use
standard.
5.1 This test method may be employed to check the sterility
1.3 This standard does not purport to address all of the
of commercially procured sterile membrane filters. The test
safety concerns, if any, associated with its use. It is the
also confirms that sterilized filters have not been contaminated.
responsibility of the user of this standard to establish appro-
Additionally, this test may be used to monitor the efficacy of
priate safety, health, and environmental practices and deter-
in-house sterilization procedures. Filter packages that have
mine the applicability of regulatory limitations prior to use.
obvious packaging defects should not be tested because steril-
1.4 This international standard was developed in accor-
ity may have been compromised.
dance with internationally recognized principles on standard-
6. Reagents and Materials
ization established in the Decision on Principles for the
6.1 Purity of Water—Unless otherwise indicated, reference
Development of International Standards, Guides and Recom-
to water shall be understood to mean Type II reagent grade
mendations issued by the World Trade Organization Technical
water in accordance with Specification D1193.
Barriers to Trade (TBT) Committee.
6.2 Media—Use commercially available dehydrated media.
2. Referenced Documents
Dissolve and sterilize by autoclaving, in accordance with the
manufacturer’s directions.
2.1 ASTM Standards:
D1129 Terminology Relating to Water 6.2.1 Fluid Thioglycollate Medium (Note)—Dispense
40-mL aliquots into suitable-sized vessels with screw-cap
D1193 Specification for Reagent Water
closure,providingaratioofsurfaceareatodepthofmediumso
2.2 Other Standard:
that no more than the upper half of the medium has initially
The United States Pharmacopeia Current Edition (Sections
undergone a color change indicative of oxygen uptake. When
on Sterilization and Sterility Testing)
readyforuse,notmorethantheupperone-tenthofthemedium
should be pink. The medium may be restored once by heating
3. Terminology
infree-flowingsteamuntilthepinkcolordisappears.ThepHof
3.1 Definitions:
the medium, after autoclaving, should be 7.1 6 0.2.
3.1.1 For definitions of terms used in this standard, refer to
NOTE 1—If stored at 2 to 5°C in sealed containers, the media may be
Terminology D1129.
used for 1 year provided they are tested for the growth-promoting
properties every 3 months.
6.2.2 Soybean-Casein Digest Medium (Note)—Dispense
This test method is under the jurisdiction of ASTM Committee D19 on Water
and is the direct responsibility of Subcommittee D19.08 on Membranes and Ion 40-mL aliquots into suitable vessels with screw-cap closure.
Exchange Materials.
The pH after autoclaving should be 7.3 6 0.2.
Current edition approved Nov. 1, 2019. Published January 2020. Originally
6.2.3 Perform a sterility test on each lot of autoclaved
approved in 1982. Last previous edition approved in 2011 as D4196 – 05 (2011).
medium by incubating ten representative containers of each
DOI: 10.1520/D4196-05R19.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
medium, for not less than 10 days, at the specified test
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
temperature.
Standards volume information, refer to the standard’s Document Summary page on
6.2.4 Perform a growth-promotion test, as described below,
the ASTM website.
Mack Publishing Co., Easton, PA 18042.
on each lot of autoclaved medium.
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D4196 − 05 (2019)
6.2.4.1 Inoculate duplicate test containers o
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