ASTM F3208-20

Standard Guide for Selecting Test Soils for Validation of Cleaning Methods for Reusable Medical Devices

SIGNIFICANCE AND USE
5.1 This guide provides information on how to select the test soil(s) that best simulates clinical use for devices. The test soil(s) selected for the validation should be clinically relevant and simulate what the device/component will come into contact with during the clinical procedure.  
5.2 This guide will help standardize the test soils used by medical device manufacturers when validating the cleaning procedures of reusable medical devices and reprocessing equipment  
5.3 For devices that come into contact with blood, the simulated test soils are blood-based soils, such as those described under 7.1.1-7.1.2.  
5.4 For devices that come into contact with mucus, the simulated test soils are those described under 7.1.3.  
5.5 For devices that come in contact with soils of a source other than the patient (e.g., bone cement), the simulated test soils should be similar to those described in 7.2. These can be used alone or in combination with 7.1.  
5.6 A combination of test soils may be used (e.g., blood with mucus) to simulate clinical soiling. For example, flexible endoscopes may come in contact with a different combination of sources of soiling (e.g., gastrointestinal (GI) tract, vasculature for biopsies) during clinical use.  
5.7 Any simulated test soil(s) or formulations can be used for simulated use testing but shall be scientifically justified by the medical device manufacturer.
SCOPE
1.1 This guide describes methods for selecting test soils for cleaning validations based upon the characteristics of the soil, the physical characteristics of the device, and the clinical use of the device.  
1.2 This guide describes the preparation and use of some test soils for the validation of cleaning instructions for reusable medical devices.  
1.3 Reusable medical devices such as endoscopes, arthroscopic shavers, surgical instruments, and suction tubes are exposed to biological soils during clinical use. Preparation of these devices for reuse requires cleaning and disinfection and/or sterilization as applicable. Adequate cleaning is the first step in a process intended to prevent contaminant transfer to the next patient and medical practitioner. The soils, if inadequately removed, can interfere with disinfection and sterilization processes, as well as performance of the device. Acceptance criteria are based either on a visual assessment or quantitatively specified marker(s) endpoint(s) of the soil or both (ISO/TS 15883-5, Section 1). Endpoints after cleaning should be based upon possible interference with disinfection/sterilization, risk to the patient or health care worker from the contaminant during further handling, and endpoints for cleaning established in the scientific literature.  
1.4 The test soils are designed to simulate the contaminants that medical devices are likely to come in contact with during clinical use. The test soils discussed in this guide are a mixture of constituents that simulate what is commonly found in human secretions, blood, tissue, and bone fragments/shavings as well as non-patient derived soil (e.g., bone cement, lubricants, and dyes) during clinical procedures. The test soils also simulate the physical parameters (e.g., viscosity, adhesion) of clinical material to which the medical devices will be exposed.  
1.5 Exclusion:  
1.5.1 This guide does not include methods to validate cleaning processes to remove residues from manufacturing  
1.5.2 This guide does not describe the soil/inoculum used for validation of disinfection or sterilization instructions. Disinfection or sterilization validation requires separate testing that is independent of cleaning validation studies.  
1.5.3 Test soils described are not intended for use by health care facilities to verify the effectiveness of their cleaning process.  
1.5.4 The test soil recipes are not intended to encompass every biological residue with which a medical device is likely to come into contact.  
1.6...

General Information

• Status: Published
• Publication Date: 14-Jul-2020
• ICS: 11.040.01 - Medical equipment in general
• ICS: 11.080.01 - Sterilization and disinfection in general
• Technical Committee: F04 - Medical and Surgical Materials and Devices
• Drafting Committee: F04.15 - Material Test Methods

Relations

• Replaces: ASTM F3208-19 - Standard Guide for Selecting Test Soils for Validation of Cleaning Methods for Reusable Medical Devices
• Effective Date: 15-Jul-2020
• Refers: ASTM D445-24 - Standard Test Method for Kinematic Viscosity of Transparent and Opaque Liquids (and Calculation of Dynamic Viscosity)
• Effective Date: 01-Apr-2024
• Refers: ASTM D445-23 - Standard Test Method for Kinematic Viscosity of Transparent and Opaque Liquids (and Calculation of Dynamic Viscosity)
• Effective Date: 01-Nov-2023
• Refers: ASTM D4287-00(2023) - Standard Test Method for High-Shear Viscosity Using a Cone/Plate Viscometer
• Effective Date: 01-Oct-2023
• Refers: ASTM D4287-00(2019) - Standard Test Method for High-Shear Viscosity Using a Cone/Plate Viscometer
• Effective Date: 01-May-2019
• Refers: ASTM D7225-13(2019)e1 - Standard Guide for Blood Cleaning Efficiency of Detergents and Washer-Disinfectors
• Effective Date: 01-May-2019
• Refers: ASTM D445-16 - Standard Test Method for Kinematic Viscosity of Transparent and Opaque Liquids (and Calculation of Dynamic Viscosity)
• Effective Date: 15-Dec-2016
• Refers: ASTM D4212-10(2014) - Standard Test Method for Viscosity by Dip-Type Viscosity Cups
• Effective Date: 01-Dec-2014
• Refers: ASTM D4287-00(2014) - Standard Test Method for High-Shear Viscosity Using a Cone/Plate Viscometer
• Effective Date: 01-Dec-2014
• Refers: ASTM D445-14e1 - Standard Test Method for Kinematic Viscosity of Transparent and Opaque Liquids (and Calculation of Dynamic Viscosity)
• Effective Date: 01-Jul-2014
• Refers: ASTM D445-14 - Standard Test Method for Kinematic Viscosity of Transparent and Opaque Liquids (and Calculation of Dynamic Viscosity)
• Effective Date: 01-Jul-2014
• Refers: ASTM D7042-14 - Standard Test Method for Dynamic Viscosity and Density of Liquids by Stabinger Viscometer (and the Calculation of Kinematic Viscosity)
• Effective Date: 01-May-2014
• Refers: ASTM D7225-13 - Standard Guide for Blood Cleaning Efficiency of Detergents and Washer-Disinfectors
• Effective Date: 01-Jun-2013
• Refers: ASTM D7042-12a - Standard Test Method for Dynamic Viscosity and Density of Liquids by Stabinger Viscometer (and the Calculation of Kinematic Viscosity)
• Effective Date: 01-Nov-2012
• Refers: ASTM D445-12 - Standard Test Method for Kinematic Viscosity of Transparent and Opaque Liquids (and Calculation of Dynamic Viscosity)
• Effective Date: 15-Apr-2012

Overview

ASTM F3208-20, "Standard Guide for Selecting Test Soils for Validation of Cleaning Methods for Reusable Medical Devices," is a key international standard developed by ASTM International. This guide provides comprehensive recommendations for medical device manufacturers on how to select clinically relevant test soils for the validation of cleaning procedures. Selection and application of appropriate test soils are fundamental for ensuring that reusable medical devices-such as endoscopes, surgical instruments, and suction tubes-are thoroughly cleaned prior to disinfection or sterilization. The standard promotes consistent and scientifically justified methods for test soil selection based on device design, intended clinical use, and typical contamination scenarios.

Key Topics

• Test Soil Selection: The guide outlines criteria for choosing test soils that accurately reflect clinical contaminants (e.g., blood, mucus, bone cement) a device may contact during use.
• Simulated Clinical Soiling: It details procedures and formulations for patient-derived soils (blood, mucus, tissue, fecal matter, skin secretions) and non-patient derived soils (bone cement, lubricants, ophthalmic substances).
• Combination of Soils: Recommendations are provided for combining test soils to mirror the composite contamination devices might experience, especially for complex devices like flexible endoscopes.
• Scientific Justification: Manufacturers are required to justify their choice of test soils, ensuring formulations are relevant and reproducible.
• Physical Characterization: The guide describes how to assess key physical properties of test soils, such as viscosity, adhesion, and solubility, using referenced ASTM methods.
• Validation Exclusions: The guide clarifies it is not intended for validating cleaning processes that remove manufacturing residues, nor for health care facilities to verify their routine cleaning effectiveness.

Applications

Medical device manufacturers and laboratories use ASTM F3208-20 to:

• Validate Cleaning Instructions: Ensure device cleaning instructions effectively remove clinically relevant contaminants before disinfection and sterilization.
• Standardize Testing: Promote uniformity in the selection and use of test soils during validation across the medical device industry.
• Meet Regulatory Requirements: Support FDA and international regulatory submissions by providing well-documented cleaning validation studies based on recognized and consistent methods.
• Improve Patient Safety: Reduce risks of device-associated infections by confirming residual soils do not hinder subsequent device disinfection or sterilization steps.
• Develop Cleaning Protocols: Establish or update internal protocols for new devices or components based on the latest standardized guidance.
• Characterize Cleaning Challenges: Assess the impact of device design, material, and soiling on cleaning efficiency to optimize device reprocessing.

Related Standards

For comprehensive validation and regulatory compliance, ASTM F3208-20 references and aligns with several other recognized standards:

• ASTM D445: Test Method for Kinematic Viscosity of Liquids
• ASTM D1193: Specification for Reagent Water
• ASTM D3330/D3330M, D3359: Methods for Adhesion Testing
• ASTM D7042, D7867: Methods for Viscosity and Density Analysis
• ASTM D7225: Guide for Blood Cleaning Efficiency of Detergents and Washer-Disinfectors
• ISO/TS 15883-5: Washer-Disinfectors-Part 5: Test Soils and Methods for Demonstrating Cleaning Efficacy
• AAMI TIR12, TIR30: Guidelines for designing, testing, labeling, and cleaning reusable medical devices
• FDA Guidance: "Reprocessing Medical Devices in Health Care Settings-Validation Methods and Labeling"

Practical Value

By following ASTM F3208-20, manufacturers contribute to standardized, scientifically defensible cleaning validation for reusable medical devices. This not only enhances patient safety and regulatory confidence but also fosters innovation in device design and reprocessing methods across the healthcare industry. Key terms relevant to this standard include medical device cleaning validation, test soil selection, reusable device reprocessing, and ASTM standard for medical cleaning.

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: F3208 − 20
Standard Guide for
Selecting Test Soils for Validation of Cleaning Methods for
Reusable Medical Devices
This standard is issued under the fixed designation F3208; 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 1.5.1 This guide does not include methods to validate
cleaning processes to remove residues from manufacturing
1.1 This guide describes methods for selecting test soils for
1.5.2 This guide does not describe the soil/inoculum used
cleaning validations based upon the characteristics of the soil,
for validation of disinfection or sterilization instructions. Dis-
thephysicalcharacteristicsofthedevice,andtheclinicaluseof
infection or sterilization validation requires separate testing
the device.
that is independent of cleaning validation studies.
1.2 This guide describes the preparation and use of some
1.5.3 Test soils described are not intended for use by health
test soils for the validation of cleaning instructions for reusable
care facilities to verify the effectiveness of their cleaning
medical devices.
process.
1.5.4 The test soil recipes are not intended to encompass
1.3 Reusable medical devices such as endoscopes, ar-
throscopic shavers, surgical instruments, and suction tubes are every biological residue with which a medical device is likely
to come into contact.
exposed to biological soils during clinical use. Preparation of
these devices for reuse requires cleaning and disinfection
1.6 Testsoilformulationsnotdescribedinthisguidemaybe
and/or sterilization as applicable.Adequate cleaning is the first
clinically relevant and may be more appropriate for simulated-
step in a process intended to prevent contaminant transfer to
use testing depending upon the clinical use of the medical
the next patient and medical practitioner. The soils, if inad-
device.The burden is upon the medical device manufacturer to
equately removed, can interfere with disinfection and steriliza-
determine and justify scientifically the selection of test soil(s).
tion processes, as well as performance of the device. Accep-
1.7 The values stated in SI units are to be regarded as the
tance criteria are based either on a visual assessment or
standard. No other units of measurement are included in this
quantitatively specified marker(s) endpoint(s) of the soil or
standard.
both (ISO/TS 15883-5, Section 1). Endpoints after cleaning
1.8 This standard does not purport to address all of the
should be based upon possible interference with disinfection/
safety concerns, if any, associated with its use. It is the
sterilization, risk to the patient or health care worker from the
responsibility of the user of this standard to establish appro-
contaminant during further handling, and endpoints for clean-
priate safety, health, and environmental practices and deter-
ing established in the scientific literature.
mine the applicability of regulatory limitations prior to use.
1.4 The test soils are designed to simulate the contaminants
1.9 This international standard was developed in accor-
that medical devices are likely to come in contact with during
dance with internationally recognized principles on standard-
clinical use. The test soils discussed in this guide are a mixture
ization established in the Decision on Principles for the
ofconstituentsthatsimulatewhatiscommonlyfoundinhuman
Development of International Standards, Guides and Recom-
secretions, blood, tissue, and bone fragments/shavings as well
mendations issued by the World Trade Organization Technical
as non-patient derived soil (e.g., bone cement, lubricants, and
Barriers to Trade (TBT) Committee.
dyes) during clinical procedures. The test soils also simulate
the physical parameters (e.g., viscosity, adhesion) of clinical
2. Referenced Documents
material to which the medical devices will be exposed.
2.1 ASTM Standards:
1.5 Exclusion:
D445 Test Method for Kinematic Viscosity of Transparent
and Opaque Liquids (and Calculation of Dynamic Viscos-
ity)
This test method is under the jurisdiction ofASTM Committee F04 on Medical
and Surgical Materials and Devices and is the direct responsibility of Subcommittee
F04.15 on Material Test Methods. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved July 15, 2020. Published August 2020. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 2017. Last previous edition approved in 2019 as F3208 – 19. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/F3208-20. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F3208 − 20
D1193 Specification for Reagent Water 3.1.5 validation, n—documented procedure for obtaining,
D3330/D3330M TestMethodforPeelAdhesionofPressure- recording, and interpreting the results required to establish that
Sensitive Tape a process will consistently yield results complying with prede-
D3359 Test Methods for Rating Adhesion by Tape Test termined specifications.
D4212 Test Method for Viscosity by Dip-Type Viscosity
3.1.5.1 Discussion—Under U.S. FDAguidelines, validation
Cups
of the instructions for cleaning is the responsibility of the
D4287 Test Method for High-Shear Viscosity Using a Cone/
medical device manufacturer.
Plate Viscometer
D7042 Test Method for Dynamic Viscosity and Density of
4. Summary of Guide
Liquids by Stabinger Viscometer (and the Calculation of
4.1 This guide provides information on the selection of test
Kinematic Viscosity)
soil formulation(s) based upon clinical use and physical
D7225 Guide for Blood Cleaning Efficiency of Detergents
characteristics of clinically occurring soiling of the device.
and Washer-Disinfectors
4.2 This guide provides the sample preparation technique
D7867 Test Methods for Measurement of the Rotational
Viscosity of Paints, Inks and Related Liquid Materials as for some test soils that simulate the soils found on medical
a Function of Temperature devices as a result of clinical use.
F2809 Terminology Relating to Medical and Surgical Mate-
4.3 An important aspect of the cleaning validation is deter-
rials and Devices (Withdrawn 2019)
mining the appropriate test soil(s) used to contaminate the
2.2 AAMI Standards:
device.
TIR12:2010 Designing, testing, and labeling reusable medi-
4.3.1 The manufacturer of the medical device or the repro-
cal devices for reprocessing in health care facilities: A
cessing equipment shall justify why the specific soil(s) was
guide for medical device manufacturers
chosen and is appropriate for all cleaning markers/assays to be
TIR30:2011 A compendium of processes, materials, test
measured.
methods, and acceptance criteria for cleaning reusable
4.3.2 The determination and selection of soil(s) shall be
medical devices
basedupontheintendedclinicaluseofthemedicaldevice.The
2.3 ISO Standard:
manufacturer needs to determine what the device will come in
ISO/TS 15883-5 Washer-disinfectors—Part 5: Test soils and
contact with (e.g., blood, mucus, cerebrospinal fluid, neuro-
methods for demonstrating cleaning efficacy
logical tissue, etc.) during clinical procedures how (e.g.,
2.4 FDA Standard: duration, complete immersion).
Reprocessing Medical Devices in Health Care Settings Vali-
4.3.3 The manufacturer should select a test soil(s) com-
dation Methods and Labeling—Guidance for Industry and posed of a formulation that includes or accurately represents
Food and Drug Administration Staff
materials that the device would likely be subjected to during
clinical use and would create the worst-case challenge to the
3. Terminology
cleaning process
4.3.4 Ideally, the formulation of the test soil should be
3.1 Definitions—Unless provided otherwise in the follow-
ing definitions, terminology shall be in conformance with composed of well-defined chemical/biochemical ingredients
and readily reproduced by any laboratory globally.
Terminology F2809.
3.1.1 cleaning, n—removal of contamination from a medi-
5. Significance and Use
cal device to the extent necessary for further processing or for
intended use.
5.1 This guide provides information on how to select the
test soil(s) that best simulates clinical use for devices. The test
3.1.2 cleaning marker, n—that which is being detected/
soil(s) selected for the validation should be clinically relevant
measured to determine soil removal/retention.
and simulate what the device/component will come into
3.1.3 contamination, n—procedure of applying simulated
contact with during the clinical procedure.
test soil onto a medical device for determination of process
5.2 This guide will help standardize the test soils used by
capability (that is, cleaning efficacy and extraction yields).
medical device manufacturers when validating the cleaning
3.1.4 test soil, n—single substance or a mixture of sub-
procedures of reusable medical devices and reprocessing
stances that reflect the contaminants likely to be encountered
equipment
during the use of the device in its intended clinical procedure.
5.3 For devices that come into contact with blood, the
simulated test soils are blood-based soils, such as those
The last approved version of this historical standard is referenced on
described under 7.1.1-7.1.2.
www.astm.org.
Available from Association for the Advancement of Medical Instrumentation
5.4 For devices that come into contact with mucus, the
(AAMI), 4301 N. Fairfax Dr., Suite 301, Arlington, VA 22203-1633, http://
simulated test soils are those described under 7.1.3.
www.aami.org.
Available from International Organization for Standardization (ISO), ISO
5.5 For devices that come in contact with soils of a source
Central Secretariat, BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernier,
other than the patient (e.g., bone cement), the simulated test
Geneva, Switzerland, http://www.iso.org.
soils should be similar to those described in 7.2. These can be
Available from U.S. Food and Drug Administration (FDA), 10903 New
Hampshire Ave., Silver Spring, MD 20993, http://www.fda.gov. used alone or in combination with 7.1.
F3208 − 20
5.6 Acombinationoftestsoilsmaybeused(e.g.,bloodwith 7.1.1 Coagulating Blood-Based Soils—Blood is often the
mucus) to simulate clinical soiling. For example, flexible only or predominant patient derived soil that medical devices
endoscopes may come in contact with a different combination come into contact with during clinical use. When this is the
of sources of soiling (e.g., gastrointestinal (GI) tract, vascula- case, the blood is likely to coagulate prior to the initiation of
ture for biopsies) during clinical use.
cleaning steps, particularly in a worst-case scenario. Coagu-
lated blood proteins are highly water insoluble and can
5.7 Any simulated test soil(s) or formulations can be used
significantly adhere to the medical device. The test soils in this
for simulated use testing but shall be scientifically justified by
section are intended to simulate the characteristics of coagu-
the medical device manufacturer.
lating blood.
6. Soil Selection Criteria
7.1.1.1 Two Component Blood Test Soil
(1) Description—A test soil correlating to coagulated
6.1 The test soils mentioned in this guide may be used to
blood is based on a proteinaceous matrix containing fibrinogen
validate cleaning procedures as long as they can be scientifi-
and thrombin in two separated components. Coagulation of the
cally justified as simulating clinical soiling.
soil is induced after mixing these two components. Guide
6.2 Other formulations or modifications to the test soil(s)
D7225 and Pfeifer (1) describe this soil in further detail.
can be made but shall be scientifically justified by the manu-
(2) Constituents—The blood test soil includes the follow-
facturer as simulating clinical soiling.
ing:
6.3 Mixtures of different soils can be made depending on
(a) Component A
how the device would be contaminated during a clinical
Albumin, bovine, protease free: 400 mg;
procedure.
Hemoglobin, bovine, lyophilized: 400 mg;
6.3.1 When selecting a combination of soils, consideration
Fibrinogen, bovine, lyophilized: 60 mg; and
shall be given to the clinical use of the device and the ratio of
Solvent A, 5.0 mL 0.4 % NaCl solution (reagent grade
the soil(s) in the combined test soil that best simulates
NaCl dissolved in sterile water).
clinically occurring soiling reflecting worst-case conditions.
(b) Component B
Albumin, bovine, protease free: 400 mg;
6.4 Contaminationbybloodduringclinicaluseisacommon
Hemoglobin, bovine, lyophilized: 400 mg;
occurrence.Therearemultiplechoicesinthekindofbloodsoil
Thrombin, reagent grade from bovine plasma: 12.5 NIH
selected for use.
units; and
6.4.1 In clinical procedures in which the predominant soil is
Solvent B, 5.0 mL 0.4 % NaCl solution (reagent grade
blood, and other agents (e.g., water for irrigation) that will not
NaCl dissolved in sterile water) + 8.0 mmol/L CaCl .
interfere with the coagulation cascade, blood that can be 2
(3) Preparation
chemically induced to coagulate is used. The coagulation
(a) The soil is prepared by separately dissolving Compo-
process is induced before soiling the device.
nentsAand B in their respective solvents by shaking for1hat
6.4.2 In clinical procedures in which blood is not the
room temperature.
predominant soil or other agents are present in sufficient
(b) Immediately before use, Components A and B are
volume to prevent coagulation, defibrinated blood is used.
mixed together in a 1:1 ratio.
NOTE 1—If whole blood is extracted without defibrination or without
(4) Markers—Suggested (not exclusive) cleaning markers
adding an anticoagulant, it forms clots and clumps. As a result, it is not
for residual analysis: protein, hemoglobin, and total organic
easily used in test soil formulations.
carbon (TOC).
6.4.3 Types of Blood:
7.1.1.2 Blood Test Soil
6.4.3.1 Defibrinated Blood—Whole blood that has been
(1) Constituents—Components of test soil include the fol-
treated to denature fibrinogen without causing cell lysis.
lowing:
6.4.3.2 Anticoagulated Whole Blood—Anticoagulated
(a) Whole sheep blood, citrated: 100 mL;
whole blood is selected in instances in which coagulation is to
(b) Bovine calf serum 50 mL;
be induced at the time of application to the device.
(c) Physiological saline solution (PHSS): 50 mL, 0.9 %
(1) Citrated Blood—Blood treated with sodium citrate to
NaCl; and
prevent coagulation. Coagulation is induced with calcium
(d) 0.01 mL of 2M CaCl .
chloride.
(2) Preparation—The soil is prepared by mixing all the
(2) Heparinized Blood—Blood rendered incoagulable by
whole blood with blood serum and the saline solution together
addition of heparin. Coagulation is induced with protamine
thoroughly. Then add the 0.01 mL of 2M CaCl calcium
sulfate.
chloride immediately before use to activate the coagulation.
7. Test Soils
NOTE 2—Because of different composition of citrated sheep’s blood
7.1 Test Soils Formulated to Simulate Patient-Derived commercially available, it may be necessary to adjust the amount of
calcium chloride used to ensure adequate coagulation.
Soils—During clinical use, the key contaminants a medical
device comes in contact with are from the patient. The soils
described in this section are formulations that are intended to
simulate the characteristics of these soils as they represent a
The boldface numbers in parentheses refer to a list of references at the end of
challenge to cleaning. this standard.
F3208 − 20
(3) Markers—Suggested (not exclusive) cleaning markers procedure, thus inhibiting the coagulation of the blood. The
for residual analysis: protein, TOC, hemoglobin, and carbohy- soils described in this section are meant to simulate clinical
drates. contaminants of this kind.
7.1.2.1 Artificial Test Soil (ATS) (2)
7.1.1.3 Blood Test Soil (BTS)
(1) Constituents
(1) Constituents
Rosewell Park Memorial Institute (RPMI) 1640: 10.4 g;
Bovine albumin: 0.5 g;
Heat inactivated Bovine Calf Serum: 100 mL;
Bovine hemoglobin: 1.0 g;
(optional) Bovine Oxgall: 20 g;
Sodium alginate: 8.3 mg;
Sterile defibrinated sheep blood: 20 % by total volume of
27 mL of sterile water for irrigation; and;
final solution;
Calcium chloride solution: 15 mM CaCl .
Sodium bicarbonate: 2 g;
(2) Preparation—Mix the albumin, hemoglobin and so-
100 mM sodium pyruvate: 10 mL;
dium alginate in a sterile container. Add the 27 mL of sterile
L-Glutamine: 10 mL of 200 mM; and
water for irrigation and calcium chloride and vortex to homog-
Total volume 1 L with distilled water.
enize the soil. Sodium alginate and calcium chloride cross link
(2) Preparation—Add the Bovine Oxgall, RPMI and so-
to form alginate hydrogels. These three-dimensional (3-D)
dium bicarbonate to a beaker. Add 700 mL of distilled water
protein hydrogels simulate the fibrin hydrogels in clotted
and mix well. Then add sodium pyruvate and L-glutamine and
blood.
again mix well. Pour this mixture into a graduated cylinder.
(3) The blood test soil may also be purchased in a ly-
Add distilled water as needed to reach a total volume in the
ophilized state.
graduated cylinder of 1 L. Filter the entire volume through a
(4) Markers—Suggested (not exclusive) cleaning markers
0.22 µL membrane filter into a sterile bottle. Using sterile
for residual analysis: protein, TOC, and hemoglobin.
technique add the sterile sheep blood and calf serum and mix
7.1.1.4 Coagulated Blood
well.
(1) Constituents—Components of test soil include the fol-
(3) The test soil may also be purchased in a lyophilized
lowing:
state.
(a) 0.1 mL heparin per 100 mL sheep blood
(4) Markers—Suggested (not exclusive) cleaning markers
(b) Protamine sulfate
for residual analysis: protein, TOC, hemoglobin, lipids and
(2) Preparation—Sheep blood is brought to room tempera-
carbohydrates.
ture prior to coagulation. Pour the heparinized blood into a
7.1.2.2 ATS2015-Bone Soil
bowl,add0.15mLofprotaminesulfatetoeach10mLofblood
(1) Constituents
and mix well. Blood should be applied immediately and
Roswell Park Memorial Institute (RPMI) 1640: 10.4 g;
coagulate in approximately 10 min to 15 min.
Heat inactivated Bovine Calf Serum: 100 mL;
(3) Markers—Suggested (not exclusive) cleaning markers
(optional) Bovine Oxgall: 20 g;
for residual analysis: protein, TOC, hemoglobin, and carbohy-
Steriledefibrinatedsheepblood:20%bytotalvolumeof
drates.
final solution;
7.1.1.5 Modified Coagulated Blood
Sodium bicarbonate: 2 g;
(1) Constituents—The test soil shall have the following
100 mM sodium pyruvate: 10 mL;
composition:
L-Glutamine: 10 mL of 200 mM;
Fresh egg yolk: 100 mL;
Total volume 1 L with distilled water;
Coagulated blood: 100 mL of coagulated blood (7.1.1.4);
Bone particulates: 0.005 g per 1 mL of Artificial Test
and
Soil (ATS).
Dehydrated hog mucin: 2 g.
(2) Preparation—Add the Bovine Oxgall, RPMI, and so-
(2) Preparation—Mix all the ingredients together thor-
dium bicarbonate to a beaker. Add 700 mL of distilled water
oughly in a blender until a liquid uniform mixture is achieved.
and mix well. Then add sodium pyruvate and L-glutamine and
Bloodshouldbeappliedimmediatelyandcoagulateinapproxi-
again mix well. Pour this mixture into a graduated cylinder.
mately 10 min to 15 min.
Add distilled water as needed to reach a total volume in the
(3) Markers—Suggested (not exclusive) cleaning markers
graduated cylinder of 1 L. Filter the entire volume through a
for residual analysis: protein, TOC, hemoglobin, and carbohy-
0.22 µL membrane filter into a sterile bottle. Using sterile
drates.
technique add the sterile sheep blood and calf serum and mix
7.1.2 Non-Coagulating Blood-Based Soils—Depending
well. Add the bone particulates to the soil.
upon the area of the body, or the nature of the clinical
(3) The test soil may also be purchased in a lyophilized
procedure, blood may be present, but coagulation of the blood
state.
does not occur. For example, while blood may be present for
(4) Markers—Suggested (not exclusive) cleaning markers
procedures in the GI tract, other contaminants are also found in
for residual analysis: protein, TOC, hemoglobin, lipids, and
such significant proportions as to inhibit the coagulation of
carbohydrates.
blood. In other procedures, such as many laparoscopic
procedures, copious water flushing is used during the 7.1.2.3 Defibrinated Blood Soil
F3208 − 20
(1) Constituents—The test soil shall have the following (1) Constituents—The test soil shall have the following
composition: composition:
Fresh egg yolk: 100 mL;
Bovine serum: 10 mL;
Defibrinated blood: 100 mL sheep blood; and Dry milk powder: 6 g; and
Dehydrated hog mucin: 2 g.
Saline (PHSS): 10 mL.
(2) Preparation—Mix all the ingredients together thor- (2) Preparation—Mix all the ingredients together thor-
oughly in a blender until a liquid uniform mixture is achieved.
oughly in an appropriate container using a hot plate (tempera-
(3) Markers—Suggested (not exclusive) cleaning markers ture between 30 and 35 °C) and a m
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: F3208 − 19 F3208 − 20
Standard Guide for
Selecting Test Soils for Validation of Cleaning Methods for
Reusable Medical Devices
This standard is issued under the fixed designation F3208; 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
1.1 This guide describes methods for selecting test soils for cleaning validations based upon the characteristics of the soil, the
physical characteristics of the device, and the clinical use of the device.
1.2 This guide describes the preparation and use of some test soils for the validation of cleaning instructions for reusable medical
devices.
1.3 Reusable medical devices such as endoscopes, arthroscopic shavers, surgical instruments, and suction tubes are exposed to
biological soils during clinical use. Preparation of these devices for reuse requires cleaning and disinfection and/or sterilization as
applicable. Adequate cleaning is the first step in a process intended to prevent contaminant transfer to the next patient and medical
practitioner. The soils, if inadequately removed, can interfere with disinfection and sterilization processes, as well as performance
of the device. Acceptance criteria are based either on a visual assessment or quantitatively specified marker(s) endpoint(s) of the
soil or both (ISO/TS 15883-5, Section 1). Endpoints after cleaning should be based upon possible interference with
disinfection/sterilization, risk to the patient or health care worker from the contaminant during further handling, and endpoints for
cleaning established in the scientific literature.
1.4 The test soils are designed to simulate the contaminants that medical devices are likely to come in contact with during clinical
use. The test soils discussed in this guide are a mixture of constituents that simulate what is commonly found in human secretions,
blood, tissue, and bone fragments/shavings as well as non-patient derived soil (e.g., bone cement, lubricants, and dyes) during
clinical procedures. The test soils also simulate the physical parameters (e.g., viscosity, adhesion) of clinical material to which the
medical devices will be exposed.
1.5 Exclusion:
1.5.1 This guide does not include methods to validate cleaning processes to remove residues from manufacturing
1.5.2 This guide does not describe the soil/inoculum used for validation of disinfection or sterilization instructions. Disinfection
or sterilization validation requires separate testing that is independent of cleaning validation studies.
1.5.3 Test soils described are not intended for use by health care facilities to verify the effectiveness of their cleaning process.
This test method is under the jurisdiction of ASTM Committee F04 on Medical and Surgical Materials and Devices and is the direct responsibility of Subcommittee
F04.15 on Material Test Methods.
Current edition approved Nov. 15, 2019July 15, 2020. Published January 2020August 2020. Originally approved in 2017. Last previous edition approved in 20182019
as F3208 – 18.F3208 – 19. DOI: 10.1520/F3208-19.10.1520/F3208-20.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F3208 − 20
1.5.4 The test soil recipes are not intended to encompass every biological residue with which a medical device is likely to come
into contact.
1.6 Test soil formulations not described in this guide may be clinically relevant and may be more appropriate for simulated-use
testing depending upon the clinical use of the medical device. The burden is upon the medical device manufacturer to determine
and justify scientifically the selection of test soil(s).
1.7 The values stated in SI units are to be regarded as the standard. No other units of measurement are included in this standard.
1.8 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.
1.9 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.
2. Referenced Documents
2.1 ASTM Standards:
D445 Test Method for Kinematic Viscosity of Transparent and Opaque Liquids (and Calculation of Dynamic Viscosity)
D1193 Specification for Reagent Water
D3330/D3330M Test Method for Peel Adhesion of Pressure-Sensitive Tape
D3359 Test Methods for Rating Adhesion by Tape Test
D4212 Test Method for Viscosity by Dip-Type Viscosity Cups
D4287 Test Method for High-Shear Viscosity Using a Cone/Plate Viscometer
D7042 Test Method for Dynamic Viscosity and Density of Liquids by Stabinger Viscometer (and the Calculation of Kinematic
Viscosity)
D7225 Guide for Blood Cleaning Efficiency of Detergents and Washer-Disinfectors
D7867 Test Methods for Measurement of the Rotational Viscosity of Paints, Inks and Related Liquid Materials as a Function
of Temperature
F2809 Terminology Relating to Medical and Surgical Materials and Devices (Withdrawn 2019)
2.2 AAMI Standards:
TIR12:2010 Designing, testing, and labeling reusable medical devices for reprocessing in health care facilities: A guide for
medical device manufacturers
TIR30:2011 A compendium of processes, materials, test methods, and acceptance criteria for cleaning reusable medical devices
2.3 ISO Standard:
ISO/TS 15883-5 Washer-disinfectors—Part 5: Test soils and methods for demonstrating cleaning efficacy
2.4 FDA Standard:
Reprocessing Medical Devices in Health Care Settings Validation Methods and Labeling—Guidance for Industry and Food and
Drug Administration Staff
3. Terminology
3.1 Definitions—Unless provided otherwise in the following definitions, terminology shall be in conformance with Terminology
F2809.
3.1.1 cleaning, n—removal of contamination from a medical device to the extent necessary for further processing or for intended
use.
3.1.2 cleaning marker, n—that which is being detected/measured to determine soil removal/retention.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
The last approved version of this historical standard is referenced on www.astm.org.
Available from Association for the Advancement of Medical Instrumentation (AAMI), 4301 N. Fairfax Dr., Suite 301, Arlington, VA 22203-1633, http://www.aami.org.
Available from International Organization for Standardization (ISO), ISO Central Secretariat, BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernier, Geneva,
Switzerland, http://www.iso.org.
Available from U.S. Food and Drug Administration (FDA), 10903 New Hampshire Ave., Silver Spring, MD 20993, http://www.fda.gov.
F3208 − 20
3.1.3 contamination, n—procedure of applying simulated test soil onto a medical device for determination of process capability
(that is, cleaning efficacy and extraction yields).
3.1.4 test soil, n—single substance or a mixture of substances that reflect the contaminants likely to be encountered during the use
of the device in its intended clinical procedure.
3.1.5 validation, n—documented procedure for obtaining, recording, and interpreting the results required to establish that a process
will consistently yield results complying with predetermined specifications.
3.1.5.1 Discussion—
Under U.S. FDA guidelines, validation of the instructions for cleaning is the responsibility of the medical device manufacturer.
4. Summary of Guide
4.1 This guide provides information on the selection of test soil formulation(s) based upon clinical use and physical characteristics
of clinically occurring soiling of the device.
4.2 This guide provides the sample preparation technique for some test soils that simulate the soils found on medical devices as
a result of clinical use.
4.3 An important aspect of the cleaning validation is determining the appropriate test soil(s) used to contaminate the device.
4.3.1 The manufacturer of the medical device or the reprocessing equipment shall justify why the specific soil(s) was chosen and
is appropriate for all cleaning markers/assays to be measured.
4.3.2 The determination and selection of soil(s) shall be based upon the intended clinical use of the medical device. The
manufacturer needs to determine what the device will come in contact with (e.g., blood, mucus, cerebrospinal fluid, neurological
tissue, etc.) during clinical procedures how (e.g., duration, complete immersion).
4.3.3 The manufacturer should select a test soil(s) composed of a formulation that includes or accurately represents materials that
the device would likely be subjected to during clinical use and would create the worst-case challenge to the cleaning process
4.3.4 Ideally, the formulation of the test soil should be composed of well-defined chemical/biochemical ingredients and readily
reproduced by any laboratory globally.
5. Significance and Use
5.1 This guide provides information on how to select the test soil(s) that best simulates clinical use for devices. The test soil(s)
selected for the validation should be clinically relevant and simulate what the device/component will come into contact with during
the clinical procedure.
5.2 This guide will help standardize the test soils used by medical device manufacturers when validating the cleaning procedures
of reusable medical devices and reprocessing equipment
5.3 For devices that come into contact with blood, the simulated test soils are blood-based soils, such as those described under
7.1.1-7.1.2.
5.4 For devices that come into contact with mucus, the simulated test soils are those described under 7.1.3.
5.5 For devices that come in contact with soils of a source other than the patient (e.g., bone cement), the simulated test soils should
be similar to those described in 7.2. These can be used alone or in combination with 7.1.
5.6 A combination of test soils may be used (e.g., blood with mucus) to simulate clinical soiling. For example, flexible endoscopes
may come in contact with a different combination of sources of soiling (e.g., gastrointestinal (GI) tract, vasculature for biopsies)
during clinical use.
F3208 − 20
5.7 Any simulated test soil(s) or formulations can be used for simulated use testing but shall be scientifically justified by the
medical device manufacturer.
6. Soil Selection Criteria
6.1 The test soils mentioned in this guide may be used to validate cleaning procedures as long as they can be scientifically justified
as simulating clinical soiling.
6.2 Other formulations or modifications to the test soil(s) can be made but shall be scientifically justified by the manufacturer as
simulating clinical soiling.
6.3 Mixtures of different soils can be made depending on how the device would be contaminated during a clinical procedure.
6.3.1 When selecting a combination of soils, consideration shall be given to the clinical use of the device and the ratio of the soil(s)
in the combined test soil that best simulates clinically occurring soiling reflecting worst-case conditions.
6.4 Contamination by blood during clinical use is a common occurrence. There are multiple choices in the kind of blood soil
selected for use.
6.4.1 In clinical procedures in which the predominant soil is blood, and other agents (e.g., water for irrigation) that will not
interfere with the coagulation cascade, blood that can be chemically induced to coagulate is used. The coagulation process is
induced before soiling the device.
6.4.2 In clinical procedures in which blood is not the predominant soil or other agents are present in sufficient volume to prevent
coagulation, defibrinated blood is used.
NOTE 1—If whole blood is extracted without defibrination or without adding an anticoagulant, it forms clots and clumps. As a result, it is not easily used
in test soil formulations.
6.4.3 Types of Blood:
6.4.3.1 Defibrinated Blood—Whole blood that has been treated to denature fibrinogen without causing cell lysis.
6.4.3.2 Anticoagulated Whole Blood—Anticoagulated whole blood is selected in instances in which coagulation is to be induced
at the time of application to the device.
(1) Citrated Blood—Blood treated with sodium citrate to prevent coagulation. Coagulation is induced with calcium chloride.
(2) Heparinized Blood—Blood rendered incoagulable by addition of heparin. Coagulation is induced with protamine sulfate.
7. Test Soils
7.1 Test Soils Formulated to Simulate Patient-Derived Soils—During clinical use, the key contaminants a medical device comes
in contact with are from the patient. The soils described in this section are formulations that are intended to simulate the
characteristics of these soils as they represent a challenge to cleaning.
7.1.1 Coagulating Blood-Based Soils—Blood is often the only or predominant patient derived soil that medical devices come into
contact with during clinical use. When this is the case, the blood is likely to coagulate prior to the initiation of cleaning steps,
particularly in a worst-case scenario. Coagulated blood proteins are highly water insoluble and can significantly adhere to the
medical device. The test soils in this section are intended to simulate the characteristics of coagulating blood.
7.1.1.1 Two Component Blood Test Soil
(1) Description—A test soil correlating to coagulated blood is based on a proteinaceous matrix containing fibrinogen and
thrombin in two separated components. Coagulation of the soil is induced after mixing these two components. Guide D7225 and
Pfeifer (1) describe this soil in further detail.
The boldface numbers in parentheses refer to a list of references at the end of this standard.
F3208 − 20
(2) Constituents—The blood test soil includes the following:
(a) Component A
Albumin, bovine, protease free: 400 mg;
Hemoglobin, bovine, lyophilized: 400 mg;
Fibrinogen, bovine, lyophilized: 60 mg; and
Solvent A, 5.0 mL 0.4 % NaCl solution (reagent grade NaCl dissolved in sterile water).
(b) Component B
Albumin, bovine, protease free: 400 mg;
Hemoglobin, bovine, lyophilized: 400 mg;
Thrombin, reagent grade from bovine plasma: 12.5 NIH units; and
Solvent B, 5.0 mL 0.4 % NaCl solution (reagent grade NaCl dissolved in sterile water) + 8.0 mmol/L CaCl .
(3) Preparation
(a) The soil is prepared by separately dissolving Components A and B in their respective solvents by shaking for 1 h at room
temperature.
(b) Immediately before use, Components A and B are mixed together in a 1:1 ratio.
(4) Markers—Suggested (not exclusive) cleaning markers for residual analysis: protein, hemoglobin, and total organic carbon
(TOC).
7.1.1.2 Blood Test Soil
(1) Constituents—Components of test soil include the following:
(a) Whole sheep blood, citrated: 100 mL;
(b) Bovine calf serum 50 mL;
(c) Physiological saline solution (PHSS): 50 mL, 0.9 % NaCl; and
(d) 0.01 mL of 2M CaCl .
(2) Preparation—The soil is prepared by mixing all the whole blood with blood serum and the saline solution together
thoroughly. Then add the 0.01 mL of 2M CaCl calcium chloride immediately before use to activate the coagulation.
NOTE 2—Because of different composition of citrated sheep’s blood commercially available, it may be necessary to adjust the amount of calcium chloride
used to ensure adequate coagulation.
(3) Markers—Suggested (not exclusive) cleaning markers for residual analysis: protein, TOC, hemoglobin, and carbohydrates.
7.1.1.3 Blood Test Soil (BTS)
(1) Constituents
Bovine albumin: 0.5 g;
Bovine hemoglobin: 1.0 g;
Sodium alginate: 8.3 mg;
27 mL of sterile water for irrigation; and;
Calcium chloride solution: 15 mM CaCl .
(2) Preparation—Mix the albumin, hemoglobin and sodium alginate in a sterile container. Add the 27 mL of sterile water for
irrigation and calcium chloride and vortex to homogenize the soil. Sodium alginate and calcium chloride cross link to form alginate
hydrogels. These three-dimensional (3-D) protein hydrogels simulate the fibrin hydrogels in clotted blood.
(3) The blood test soil may also be purchased in a lyophilized state.
(4) Markers—Suggested (not exclusive) cleaning markers for residual analysis: protein, TOC, and hemoglobin.
7.1.1.4 Coagulated Blood
(1) Constituents—Components of test soil include the following:
(a) 0.1 mL heparin per 100 mL sheep blood
(b) Protamine sulfate
(2) Preparation—Sheep blood is brought to room temperature prior to coagulation. Pour the heparinized blood into a bowl,
add 0.15 mL of protamine sulfate to each 10 mL of blood and mix well. Blood should be applied immediately and coagulate in
approximately 10 min to 15 min.
(3) Markers—Suggested (not exclusive) cleaning markers for residual analysis: protein, TOC, hemoglobin, and carbohydrates.
7.1.1.5 Modified Coagulated Blood
(1) Constituents—The test soil shall have the following composition:
Fresh egg yolk: 100 mL;
Coagulated blood: 100 mL of coagulated blood (7.1.1.4); and
Dehydrated hog mucin: 2 g.
F3208 − 20
(2) Preparation—Mix all the ingredients together thoroughly in a blender until a liquid uniform mixture is achieved. Blood
should be applied immediately and coagulate in approximately 10 min to 15 min.
(3) Markers—Suggested (not exclusive) cleaning markers for residual analysis: protein, TOC, hemoglobin, and carbohydrates.
7.1.2 Non-Coagulating Blood-Based Soils—Depending upon the area of the body, or the nature of the clinical procedure, blood
may be present, but coagulation of the blood does not occur. For example, while blood may be present for procedures in the GI
tract, other contaminants are also found in such significant proportions as to inhibit the coagulation of blood. In other procedures,
such as many laparoscopic procedures, copious water flushing is used during the procedure, thus inhibiting the coagulation of the
blood. The soils described in this section are meant to simulate clinical contaminants of this kind.
7.1.2.1 Artificial Test Soil (ATS) (2)
(1) Constituents
Rosewell Park Memorial Institute (RPMI) 1640: 10.4 g;
Heat inactivated Bovine Calf Serum: 100 mL;
(optional) Bovine Oxgall: 20 g;
Sterile defibrinated sheep blood: 20 % by total volume of final solution;
Sodium bicarbonate: 2 g;
100 mM sodium pyruvate: 10 mL;
L-Glutamine: 10 mL of 200 mM; and
Total volume 1 L with distilled water.
(2) Preparation—Add Add the Bovine Oxgall, RPMI and sodium bicarbonate to a beaker. Add 700 mlmL of distilled water
and mix well. Then add sodium pyruvate and L-glutamine and again mix well. Pour this mixture into a graduated cylinder. Add
distilled water as needed to reach a total volume in the graduated cylinder of 1 L. Filter the entire volume through a 0.22 μL
membrane filter into a sterile bottle. Using sterile technique add the sterile sheep blood and calf serum and mix well.
(3) The test soil may also be purchased in a lyophilized state.
(4) Markers—Suggested (not exclusive) cleaning markers for residual analysis: protein, TOC, hemoglobin, lipids and
carbohydrates.
7.1.2.2 ATS2015-Bone Soil
(1) Constituents
Roswell Park Memorial Institute (RPMI) 1640: 10.4 g;
Heat inactivated Bovine Calf Serum: 100 mL;
(optional) Bovine Oxgall: 20 g;
Sterile defibrinated sheep blood: 20 % by total volume of final solution;
Sodium bicarbonate: 2 g;
100 mM sodium pyruvate: 10 mL;
L-Glutamine: 10 mL of 200 mM;
Total volume 1 L with distilled water;
Bone particulates: 0.005 g per 1mL 1 mL of Artificial Test Soil (ATS).
(2) Preparation—Add the Bovine Oxgall, RPMI, and sodium bicarbonate to a beaker. Add 700 mL of distilled water and mix
well. Then add sodium pyruvate and L-glutamine and again mix well. Pour this mixture into a graduated cylinder. Add distilled
water as needed to reach a total volume in the graduated cylinder of 1 L. Filter the entire volume through a 0.22 μL membrane
filter into a sterile bottle. Using sterile technique add the sterile sheep blood and calf serum and mix well. Add the bone particulates
to the soil.
(3) The test soil may also be purchased in a lyophilized state.
(4) Markers—Suggested (not exclusive) cleaning markers for residual analysis: protein, TOC, hemoglobin, lipids, and
carbohydrates.
7.1.2.3 Defibrinated Blood Soil
(1) Constituents—The test soil shall have the following composition:
Fresh egg yolk: 100 mL;
Defibrinated blood: 100 mL sheep blood; and
Dehydrated hog mucin: 2 g.
(2) Preparation—Mix all the ingredients together thoroughly in a blender until a liquid uniform mixture is achieved.
(3) Markers—Suggested (not exclusive) cleaning markers for residual analysis: protein, TOC, hemoglobin, and carbohydrates.
7.1.2.4 Simulated Ophthalmic Test Soil (3)
F3208 − 20
(1) Constituents—The test soil shall have the following composition:
Dried egg yolk: 0.8 g;
Defibrinated blood: 10 mL (horse or sheep); and
D
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