Designation:F2148−18StandardPracticeforEvaluationofDelayedContactHypersensitivityUsingtheMurineLocalLymphNodeAssay(LLNA)1ThisstandardisissuedunderthefixeddesignationF2148;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thispracticeprovidesamethodologytouseacombi-nationofinvivioandinsituproceduresfortheevaluationofdelayedcontacthypersensitivityreactions.1.2Thispracticeisintendedtoprovideanalternativetotheuseofguineapigsforevaluationoftheabilityofadevicematerialtostimulatedelayedcontacthypersensitivityreac-tions.Thisalternativeisparticularlyapplicableformaterialsusedindevicesthatcontactonlyintactskin.However,theguineapigmaximizationtestisstilltherecommendedmethodwhenassessingthedelayedhypersensitivityresponsetometalsorwhentestingsubstancesthatdonotpenetratetheskinbutareusedindevicesthatcontactdeeptissuesorbreachedsurfaces.Thispracticemaybeusedfortestingmetals,withtheexcep-tionofnickel-containingmetals,unlesstheuniquephysico-chemicalpropertiesofthematerialsmayinterferewiththeabilityofLLNAtodetectsensitizingsubstances.1.3Thispracticeconsistsofaprotocolforassessinganincreaseinlymphocyteproliferationinthelymphnodesdrainingthesiteoftestarticleadministrationontheearsofmice.1.4TheLLNAhasbeenvalidatedonlyforlow-molecular-weightchemicalsthatcanpenetratetheskin.Theabsorbedchemicalormetabolitemustbindtomacromolecules,suchasproteins,toformimmunogenicconjugates.1.5Thispracticeisoneofseveraldevelopedfortheassessmentofthebiocompatibilityofmaterials.PracticeF748mayprovideguidancefortheselectionofappropriatemethodsfortestingmaterialsforaspecificapplication.1.6Identificationofasupplierofmaterialsorreagentsisfortheconvenienceoftheuseranddoesnotimplyasinglesource.Appropriatematerialsandreagentsmaybeobtainedfrommanycommercialsupplyhouses.1.7ThevaluesstatedinSIunitsareto...
