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Designation:E1837–96(Reapproved2002)StandardTestMethodtoDetermineEfficacyofDisinfectionProcessesforReusableMedicalDevices(SimulatedUseTest)1ThisstandardisissuedunderthefixeddesignationE1837;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(e)indicatesaneditorialchangesincethelastrevisionorreapproval.INTRODUCTIONWhenspecialtestsdesignedtoregisterorvalidateadisinfectionprocesscurrentlyareused,theprocedures,theirstatisticalconsiderations(usuallyallnegativesatagiventimepoint),andthephysicalproblemsofapplyingorganismstosurfaces,suchassuturesandunglazedporcelaincarriers,maycauseinaccurateandconfusingresults.Practical,in-usetestingofreprocessingtechniquesandconditionsareneeded.Exaggeratedconditionsfortestingcanbeachievedwiththeuseofactualinstrumentscontaminatedwithhighnumbersoforganisms.Theadditionofserumasanorganicloadorhardwatermineralsasaninorganicloadcanbemadetoenhanceworst-caseconditions.Whentheseelementsarecoupledwiththeprocessing,asactuallyperformed,theresultisastructuredtestthatisasimulated-useprocedure.Thistestmethodisdesignedtoincorporateseveralelementsofreprocessing,includingcleaning,rinsing,anddisinfection(includingoptionaltreatmentoftheinternalchannelsofdevices,suchasendoscopes)withaterminalalcoholrinseratherthanexaminingonlytheeffectivenessoftheentiredisinfectionprocess.Asimulated-usetesttoexaminetheeffectivenessofreprocessingproceduresisvaluablebecauseseveralincidentsofcontaminationofinstrumentsinusehavebeenrecordedwithvegetativecellsofbacteria,forexample,Pseudomonasandthemycobacteria.Whenthisprocedureisperformedwitharepresentativemycobacterialculture,itisnecessarytouseanonpathogenicstrainsuchasMycobacteriumterrae(isolatedfromsoil)thatcanbemanipulatedonanopenbench.ThisstrainisusedintuberculocidaltestinginEurope,andpublishedinformationshowscomparableresistancetoantimicrobialsasthatdisplayedbyhumantuberculosisstrainsofMycobacteriumtuberculosis.Thisorganismcanbehandledeasilyandgrowsfasterthanotherteststrains,suchasM.bovis.(1,2,3,4,and5).2Becausecontaminationofthesurfacesofinstrumentshasoccurredfromrinsingwithtapwater,bacteria-freewatershouldbeusedforallrinsingduringreprocessinginthistestprocedurewhenawaterrinsestepispartofthereprocessingdirections.1.Scope1.1Thistestmethodisintendedtodescribeaprocedurefortestingtheeffectivenessofadisinfectionprocessforreprocess-ingreusablemedicaldeviceswhenitistestedwithachallengeofvegetativecellsincludingmycobacteria.Disinfectionnor-mallydealswithtestingactivityagainstvegetativecellsofbacteria,viruses,andfungi.Sincethistestmethodisprocessoriented,theusermaywishtoexamineavarietyoftestorganisms.1.2Thistestmethodisdesignedtoprovideareproducibleproceduretoverifytheeffectivenessofapreviouslyvalidateddisinfectantordisinfectionprocedureforreusablemedicalinstrumentsanddevices.1.3Thistestmethodisnotmeanttodefinetheeffectivenessoforvalidationoftheparticulardisinfectionprocessusedoritskinetics,butrather,itisdevisedtoconfirmtheeffectivenessofthedisinfectionprocessbysimulatingusesituationswithaparticulartestprocessusingmedicaldevicesandinstruments.Eithermanualormachinereprocessingcanbetested.1ThistestmethodisunderthejurisdictionofASTMCommitteeE35onPesticidesandAlternativeControlAgentsandisthedirectresponsibilityofSubcommitteeE35.15onAntimicrobialAgents.CurrenteditionapprovedOct.10,2002.PublishedMarch2003.Originallyapprovedin1996.Lastpreviouseditionapprovedin1996asE1837–96.2Theboldfacenumbersinparenthesesrefertothelistofreferencesattheendofthisstandard.1Copyright©ASTMInternational,100BarrHarborDrive,POBoxC700,WestConshohocken,PA19428-2959,UnitedStates.1.4Thistestmethodisintendedforusewithreusablecleanedandpreviouslysterilizedordisinfected(highlevel)medicalinstrumentsanddevices.Endoscopesaredescribedinthistestmethodasaworst-caseexampleforcontaminationandsampling.Theselectedsterilizationordisinfectionprocesses,orboth,shouldhavebeenvalidatedpreviously,aswellastheeffectivenessofrinsingforresidualsterilant/disinfectantre-movaldetermined.1.5Aninoculumwithhighnumbersofselectedmicroor-ganismsisappliedtobothtestandcontrol,cleanedandsterilized,ordisinfectedmedicalinstruments.Strainsofmi-croorganismswitharecordedresistancetodisinfectantsareusedtocontaminatetheinstrumentsitesknownorsuspectedtobethemostdifficulttoreprocess.1.6Itisimpracticaltotestforrecoveryofsurvivorsbyimmersionofsomeinstruments,forexample,endoscopesorsomelaproscopicinstruments,ingrowthmediumbecauseofcomplexity,size,difficultyinlong-termincubation,ordeteri-ouseffectsresultingfromincubation.Elutionoforganismsfromtheinoculatedsurfaces,therefore,maybeperformedtoestimatethenumberofrecoverableorganisms.Immersioncanbeusedforsmallerinstruments.1.7Controlinstrumentsareinoculatedinthesamemannerasthetestinstrumentsandelutionorimmersionmethodsareperformedtodeterminethenumberoforganismsrecoverablefromtheinstrument.Forchanneleddevices,suchasendo-scopestesting,thenumberoforganismsrecoverablefromthei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