Residual Organic Soils on Patient used Instruments Key Considerations for User Verifcation Ralph J Basile, MBA Vice President Healthmark Ind. Co., Inc.
What types of soil found on patient-used instruments? blood carbohydrates synovial fluids lipids bone tissue other
Is there one soil or marker that is present on all patient used instruments? Protein Adenosine Triphosphate (ATP) Total Organic Carbon (TOC) Others?
Protein Advantages Present in almost any human secretion can identify. Present in other microbial contamination. Are quick and well studied methods for testing. Disadvantages False positives? Protein is so ubiquitous that poor testing technique could yield a result (i.e., fingerprints) Is it harmful? Being so ubiquitous, it is not possible to determine whether a threat to patient (if present must assume harmful). Steps in reprocessing can render it difficult to detect (denaturing and insoluble).
ATP (adenosine triphosphate) Advantages Is present in bacteria and viable human cells. Quick and easy to interpret test are available. Provides a numeric result, more objective than colormetric result. Disadvantages Like protein, ubiquitous nature can lead to false positives. ATP degrades rapidly, particularly in presence of reprocessing conditions (heat, detergents) rendering it undetectable even when organic soils remain. Like protein, what is a safe level?
TOC (total organic carbon) Advantages Carbon is present in all organic soils. Quick test methods are available. Disadvantages Like protein and ATP, ubiquioutous nature can lead to false positives. Like the other two markers, what is a safe level? Currently available test methods necessitate reprocessing any instrument which is tested.
More Specific Soils/Markers for Specific Instruments (i.e. hemoglobin)? Advantages Reduce chance for false positives. Provide faster results. More sensitive tests (lower level of detection. Can identify the risk (in case of blood - none should remain to eliminate risk to patient). Disadvantages Reprocessing staff need to be better educated - which test for which instrument. Greater the number of tests, the greater the diversity of results (e.g., different colors, or different numbers, etc.).
Commercial products in the market hemoglobin sensitive down to 0.1ug hemoglobin. colormetric result - easy to interpret. limited chance for false positives (e.g., oxidizing agents which might be in cleaners or disinfectants). not appropriate for all instruments.
Commercial products in the market, cont'd multi-parameter test strip hemoglobin/protein/carbohydrates. colormetric result - easy to interpret. flush method lends itself to testing lumens, but not external surfaces. not as sensitive as specific tests.
Commercial products in the market, cont'd protein variety of available tests. all feature a colorimetric result that is easy to interpret. some will only work for soluble proteins - which often is not the state of proteins after reprocessing. some take an extended time to detect insoluble proteins. sensitivity levels vary between products - confusion for users. susceptible to false positives.
Commercial products in the market, cont'd ATP Tests quick result (less than 1 minute). provides an objective measure (number). ATP is prevalent with viable cells/organisms. ATP degrades over time and that is accelerated in the conditions of reprocessing. Organic soils may remain when ATP no longer present. Different brands of tests have different RLU scales - confusion for users.
Surrogate Device - An alternative solution For some device manufacturers, the best solution may be to provide or recommend a surrogate test device rather than specify the soil and methods for testing: Can be simple pass/fail. Will have the "right soil" for the target device. Can be "visually" clean not requiring chemistry, readers, etc. Only for automated processes - not appropriate for manual cleaning
Questions for the Summit to consider: Is there a universal soil/marker that is always present on patient-used instruments? Or should the marker(s) change with the device? Is (are) there a soil(s)/marker(s) that can be practically tested for in non-lab setting? What interference will reprocessing steps cause in testing for targeted soil(s)? Is a surrogate testing device a better option when practical? What is a safe level? What is clean? What is the level of detection? What guidance can we give the user for frequency of testing, etc.?
References AAMI Documents: AAMI TIR30:2011: A compendium of processes, materials, test methods, and acceptance criteria for cleaning reusable medical devices AAMI TIR12:2010: Designing, testing, and labeling reusable medical devices for reprocessing in health care facilities: A guide for medical device manufacturers ANSI/AAMI ST79:2010 & A1:2010: Comprehensive guide to steam sterilization and sterility assurance in health care facilities ANSI/AAMI ST15883-1:2009 (ISO 15883-1:2006, MOD), Washer-disinfectors, Part 1: General requirements, terms and definitions and tests ISO/TS 15883-5:2005, Washer-disinfectors - Part 5: Test soils and methods for demonstrating cleaning efficacy of washerdisinfectors Other Reference Documents: Alfa, MJ. Artificial Test Soil. US Patent 6,447,990; 2002 Alfa MJ, DeGagne P, and Olson N. Worstcase soiling levels for patient-used flexible endoscopes before and after cleaning. Am J Infect Control, 27:392 401, 1999 Alfa MJ, Olson N, and Buelow-Smith L. Simulated-use testing of bedpan and urinal washer disinfectors: Evaluation of Clostridium difficile spore survival and cleaning efficacy. Am J Infect Control, 36(1):5 11, 2008 Association of perioperative Registered Nurses. Recommended practices for cleaning and care of surgical instruments and powered equipment. In: Perioperative standards and recommended practices. Denver: AORN, 2011a ASTM International. Standard guide for blood cleaning efficiency of detergents and washer disinfectors. ASTM D7225-06. Philadelphia (PA): ASTM International, 2006
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