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1、Compatibility TestingAhmad Shihada Silmi Msc, FIBMSIUGWhat is compatibility testing?Also called pretransfusion testingAlso called pretransfusion testingPurposePurpose: :l lTo select blood components that will not cause harm To select blood components that will not cause harm to the recipient and wil
2、l have acceptable survival to the recipient and will have acceptable survival when transfusedwhen transfusedIf properly performed, compatibility tests will If properly performed, compatibility tests will confirm ABO compatibility between the confirm ABO compatibility between the component and the re
3、cipient and will detect the component and the recipient and will detect the most clinically significant unexpected antibodiesmost clinically significant unexpected antibodiesCompatibility testing?There are several components of compatibility testingl lProper specimen collectionProper specimen collec
4、tionl lReviewing patient transfusion historyReviewing patient transfusion historyl lABO, Rh, and antibody testing (screen/ID)ABO, Rh, and antibody testing (screen/ID)l lCrossmatchingCrossmatchingl lActual transfusionActual transfusionCompatibility testingCan be divided into 3 categories:l lPreanalyt
5、icalPreanalytical procedures proceduresl lSerological testingSerological testingl lPostanalyticalPostanalytical procedures proceduresPre-analytical phasesPatient identificationSpecimen collectionReview of patient historyPatient IdentificationMust confirm Must confirm recipients ID from recipients ID
6、 from bracelet ON the bracelet ON the patientpatientl lFull patient name and Full patient name and hospital numberhospital numberl lName of physicianName of physicianhttp:/ IdentificationThe sample should The sample should also have the full also have the full patient name, hospital patient name, ho
7、spital number, and number, and physicianphysicianDate and time of Date and time of collection, collection, phlebotomists initialsphlebotomists initialsAll of this should be All of this should be on the request form on the request form and the sampleand the sampleSpecimen TubesPink Top - EDTARed Top
8、no additivesSpecimen CollectionCollected in tube with EDTA or no additivesCollected in tube with EDTA or no additivesIf the If the venipuncturevenipuncture causes causes hemolysishemolysis, the , the sample may be rejectedsample may be rejectedTrue True hemolysishemolysis in the patient is the resul
9、t of in the patient is the result of complement activationcomplement activationSamples are labeled at the bedside (pre-labeling Samples are labeled at the bedside (pre-labeling is not recommended)is not recommended)A record of individuals who collect (or test) the A record of individuals who collect
10、 (or test) the specimens should be documented in order to specimens should be documented in order to “backtrack” in case of an error“backtrack” in case of an errorSpecimen CollectionIf the sample is drawn from an IV line, the IV infusion should be stopped 5-10 minutes prior to blood drawing and the
11、first 10 mL discardedTesting should be performed on samples less than 72 hours or else complement dependent antibodies may be missed (complement can become unstable)Getting the historyLook at recipients records for any prior unexpected antibodiesPrevious transfusion reactionsSerological Testing3 tes
12、ts:l lABO/ABO/RhRhl lAntibody detection/identificationAntibody detection/identificationl lCrossmatch Crossmatch ABO/Rh TypingIn the ABO typing, the forward and reverse MUST matchIn the Rh typing, the control must be negativeBoth of these will indicate what type of blood should be givenAntibody scree
13、n and/or IDThe antibody screen will detect the presence of The antibody screen will detect the presence of any unexpected antibodies in patient serumany unexpected antibodies in patient serumIf antibodies are detected, identification should If antibodies are detected, identification should be perfor
14、med using panel cells (with an be performed using panel cells (with an autocontrol)autocontrol)l lISISl l3737 (LISS) (LISS)l lAHGAHGIf an antibody is present, units negative for the If an antibody is present, units negative for the antigen must be given antigen must be given Proceed to the crossmatc
15、hProceed to the crossmatchCrossmatchingPurpose:l lPrevent transfusion reactionsPrevent transfusion reactionsl lIncrease Increase in vivoin vivo survival of red cells survival of red cellsl lDouble checks for ABO errorsDouble checks for ABO errorsl lAnother method of detecting antibodiesAnother metho
16、d of detecting antibodiesCrossmatchTwo types of crossmatchesl lMajor routinely performed in labsMajor routinely performed in labsl lMinor not required by AABB since 1976Minor not required by AABB since 1976HistoryMajor vs Minor CrossmatchWhy is the minor Why is the minor crossmatch crossmatch unnece
17、ssary?unnecessary?l lDonated units are Donated units are tested for antibodiestested for antibodiesl lMost blood is Most blood is transfused as packed transfused as packed cells, having little cells, having little antibodiesantibodiesCrossmatches The AABB and FDA develop the standards for blood bank
18、ingAccording to the AABB Standards:The crossmatch “shall use methods that The crossmatch “shall use methods that demonstrate ABO incompatibility and clinically demonstrate ABO incompatibility and clinically significant antibodies to red cell antigens and significant antibodies to red cell antigens a
19、nd shall include an antiglobulin phase”shall include an antiglobulin phase”Crossmatch Donor RBCs (washed)Patient serumNo agglutination compatibleAgglutination incompatibleThe procedureDonor cells are taken Donor cells are taken from from segmentssegments that that are attached to the are attached to
20、 the unit itselfunit itselfSegments are a Segments are a sampling of the blood sampling of the blood and eliminate having and eliminate having to open the actual unitto open the actual unitUnits of whole blood with segments attachedProcedureABO/Rh typing is FIRST performedAntibody Screen is performe
21、d next.Crossmatch Procedure if antibodies are NOT detected:l lOnly immediate spin (IS) is performed using Only immediate spin (IS) is performed using patient serum and donor blood suspensionpatient serum and donor blood suspensionl lThis fulfills the AABB standard for ABO This fulfills the AABB stan
22、dard for ABO incompatibilityincompatibilityl lThis is an This is an INCOMPLETE CROSSMATCHINCOMPLETE CROSSMATCHIf antibodies ARE detected:l lAntigen negative units found and X-matchedAntigen negative units found and X-matchedl lAll phases are tested: IS, 37, AHGAll phases are tested: IS, 37, AHGl lTh
23、is is a This is a COMPLETE CROSSMATCHCOMPLETE CROSSMATCHCrossmatches WillVerify donor cell ABO compatibilityDetect most antibodies against donor cellsWill NotGuarantee normal survival of RBCsPrevent patient from developing an antibodyDetect all antibodiesPrevent delayed transfusion reactionsDetect A
24、BO/Rh errorsIncompatible crossmatchesAntibody Antibody screenscreenCrossmatchCrossmatchCause Cause ResolutionResolutionPosPosNegNegAntibody directed Antibody directed against antigen on against antigen on screening cellscreening cellID antibody, select ID antibody, select antigen negative antigen ne
25、gative bloodbloodNegNegPosPosAntibody directed Antibody directed against antigen on against antigen on donor cell which may donor cell which may not be on screening not be on screening cell cell OROR donor unit donor unit may have may have IgGIgG previously attachedpreviously attachedID antibody, se
26、lect ID antibody, select antigen negative antigen negative blood blood OROR perform perform DAT on donor unitDAT on donor unitPosPosPosPosAntibodies directed Antibodies directed against both against both screening and donor screening and donor cellscellsAntibody ID, select Antibody ID, select antige
27、n negative antigen negative bloodbloodAdditional Information on Types of Compatibility TestsManual (IS and IAT)Gel TechnologyElectronic (Computerized) Cross matchRed cell Affinity Column Technology (ReACT) Solid Phase Adherence Assays (SPAA)Manual (IS and IAT)IS detect RT reactive antibodies (Auto,
28、Alloantibody, Naturally IS detect RT reactive antibodies (Auto, Alloantibody, Naturally occuring)occuring)IAT detect IgG antibodies (Auto & alloantibody)IAT detect IgG antibodies (Auto & alloantibody)AntibodyNaturallyoccuring(Coldagglutinin)AcquiredAutoantibodyAlloantibodyGel TechnologyPatient serum
29、, and 1% of suspended Patient serum, and 1% of suspended RBCs in LIM are dispensed into the RBCs in LIM are dispensed into the microtube and incubated at 37microtube and incubated at 37o oC for 15 C for 15 minutes.minutes.The card containing the microtubes is The card containing the microtubes is th
30、en centrifuged at a controlled speed then centrifuged at a controlled speed for 10 minutes.for 10 minutes.At the start of centrifugation the cells At the start of centrifugation the cells are separated from the serum; then are separated from the serum; then they meet the AHG contained in the they me
31、et the AHG contained in the microtubemicrotube. . Finally the cells are trapped by the gel Finally the cells are trapped by the gel (if agglutinated) or pellet to the bottom (if agglutinated) or pellet to the bottom of the tube.of the tube.X Match PhasesPHASEPHASEPURPOSEPURPOSEDETECTSDETECTS IS IS d
32、etection IgM detection IgM cold agglutinin cold agglutinin Most ABO Most ABO incompatibilitiesincompatibilities3737o oC, LISSC, LISSIgG Abs IgG Abs Potent Rh AbsPotent Rh AbsAHGAHGIgG AbsIgG AbsRh, Duffy, Kidd, othersRh, Duffy, Kidd, othersOCCOCCAHG absence, AHG absence, inadequacy, or inadequacy, o
33、r neutralizationneutralizationSensitized RBCsSensitized RBCsclinicallyinsignificantsuchasanti-M,-N,-Lea,-Leb,and-I.ThisphaseisusuallyreadonlymacroscopicallyforagglutinationThisphaseisreadmicroscopicallyforagglutinationaddedtoallnegativetestsandmustproduceapositiveresult Limitations of Pretransfusion
34、 TestingHemolytic transfusion reaction, if the patients Hemolytic transfusion reaction, if the patients antibody is too weak to be detected.antibody is too weak to be detected.Standard antibody detection methods such as Standard antibody detection methods such as the indirect antiglobulin test requi
35、re several 100 the indirect antiglobulin test require several 100 antibody molecules per red cell to produce antibody molecules per red cell to produce detectable reactions. detectable reactions. A hemolytic transfusion reaction due to patient A hemolytic transfusion reaction due to patient misident
36、ification. For example, group A red cells misidentification. For example, group A red cells (meant for transfusion to a group O recipient) will (meant for transfusion to a group O recipient) will be compatible in vitro tests with an incorrect be compatible in vitro tests with an incorrect specimen d
37、rawn from a group A person. specimen drawn from a group A person. Limitations of Pretransfusion TestingHemolytic transfusion reaction if donor red Hemolytic transfusion reaction if donor red cells are inadvertently hemolysed before cells are inadvertently hemolysed before entering the patient, e.g.,
38、 red cells hemolysed entering the patient, e.g., red cells hemolysed by an improperly functioning blood warmer or by an improperly functioning blood warmer or red cells hemolysed by contact with an ice red cells hemolysed by contact with an ice pack in a transport container.pack in a transport conta
39、iner.NonhemolyticNonhemolytic transfusion reactions such as transfusion reactions such as allergic, febrile, and other reactions. allergic, febrile, and other reactions. Pretransfusion test are meant to detect only Pretransfusion test are meant to detect only red cell antibodies. red cell antibodies
40、. Incompatible cross matchABO incompatibility Recheck patient and blood unit ABO Recheck patient and blood unit ABO groupgroupClinically Significant AbDAT & IATDAT & IATAntibody Detection IATIAT is used to detect clinically significantIAT is used to detect clinically significant IgG antibodies bound
41、 to RBCS IgG antibodies bound to RBCS in vitro.in vitro.Detection of free Abs in patients serum.Detection of free Abs in patients serum.Clinically significant IgG Abs cause hemolysis or Clinically significant IgG Abs cause hemolysis or reduce survival of transfused RBCs, like D, c, E, K, reduce surv
42、ival of transfused RBCs, like D, c, E, K, k, JKk, JKa a, JK, JKb b, FY, FYa a, FY, FYb b , S, s., S, s.Unimportant Abs: I, PUnimportant Abs: I, P1 1, Le, Lea a, Le, Leb b, M, N., M, N.Those Abs are Unimportant due toThose Abs are Unimportant due toMostly cold reactive (IgM)Mostly cold reactive (IgM)
43、Could be neutralizedCould be neutralizedIAT is principally used forAb detectionAb investigation (identification)Ab titrationCompatibility testing Phenotyping for some RBCs antigensReagent used in IATCharacteristics of RBCs reagent: :Three cell reagent sets, Serocyte I, II, III.Three cell reagent set
44、s, Serocyte I, II, III.RBCs antigens corresponding to important RBCs antigens corresponding to important and clinically significant Abs.and clinically significant Abs.The reagent cells are suspended in saline The reagent cells are suspended in saline and 2%-5% antibiotic.and 2%-5% antibiotic.Expired
45、 reagent should not be used.Expired reagent should not be used.An antigram defining phenotype of reagent An antigram defining phenotype of reagent cell must included with every cell.cell must included with every cell.All reagent should be stored at 1-6All reagent should be stored at 1-6o oC.C.Perfor
46、mance IATMost clinically significant Abs react at 37Most clinically significant Abs react at 37o oC, C, RT and IS are not required. RT and IS are not required.AHG is usually monospecific IgGAHG is usually monospecific IgGNo need for polyspecific AHG.No need for polyspecific AHG.BecauseBecause Anti C
47、 will detect Abs during the incubation phase. Anti C will detect Abs during the incubation phase.Anti C enhance the detection of cold agglutinin such Anti C enhance the detection of cold agglutinin such as anti I, anti P that are non significant Abs and not as anti I, anti P that are non significant
48、 Abs and not important in transfusion.important in transfusion.Delaying transfusion in critical situations. Delaying transfusion in critical situations. Interpretation Result of IATNegative IATOCC Positive: Report IAT negative Positive IAT Perform:l lAb identification.Ab identification.l lAb titrati
49、on.Ab titration.Interpretation Result of IATLow titer, and weak reactive Abs are failed to be detected Using commercial reagents include RBCs that Using commercial reagents include RBCs that express important antigens in double dose, as JK express important antigens in double dose, as JK (a + b -),
50、JK Fy and Fy (a + b -), Fy (a + b -) cells.(a + b -), JK Fy and Fy (a + b -), Fy (a + b -) cells.Avoiding use of LISS Avoiding use of LISS LISS enhance reactivity of cold reactive Abs LISS enhance reactivity of cold reactive Abs causingcausing difficulties in detection clinically significant Abs . d
51、ifficulties in detection clinically significant Abs .Increase amount of serum to increase amount of Increase amount of serum to increase amount of Abs. Abs. Its not a life threatening situation when an unexpected clinically important Abs to an RBCs Ags in a blood unit is not detected, BecauseThe pla
52、sma volume is small, and Abs will be diluted in recipient circulationUnlikely to cause significant destruction to recipients RBCs. Antibody Identification0.3% - 2.8% of the 0.3% - 2.8% of the population are population are Ab makers,Ab makers, they produce clinically they produce clinically significa
53、nt Ab.significant Ab.Pregnancy and transfusion Pregnancy and transfusion are the common cause of are the common cause of immunization to RBCs Ags.immunization to RBCs Ags.Serological PropertiesAbs of blood groups vary in importance Abs of blood groups vary in importance and significance due to serol
54、ogical and significance due to serological propertiespropertiesTemperature phase Temperature phase 3737o oC reactive Abs as anti D, c, E, K, k, JKC reactive Abs as anti D, c, E, K, k, JKa a, , JKJKb b, FY, FYa a, FY, FYb b , S, s., S, s.Cold agglutinin as anti LeCold agglutinin as anti Lea a, Le, Le
55、b b, I, P1, M, N., I, P1, M, N.Inducing HDN and HTRInducing HDN and HTR Activation complement. Activation complement.Neutralizing by soluble blood group AgsNeutralizing by soluble blood group AgsProblems Encountered Autoantibody directed against own cell Ags solutionElution IgG Abs can be dissociate
56、d from RBCs membrane IgG Abs can be dissociated from RBCs membrane Ags by physical or chemical means, some procedures Ags by physical or chemical means, some procedures destroy membrane, some leave it intact.destroy membrane, some leave it intact. Supernatant fluid (elute) contain the autoantibodies
57、 Supernatant fluid (elute) contain the autoantibodies which can be identified. which can be identified. Problems EncounteredCombination of auto and alloantibodyCombination of auto and alloantibody solution solutionTreatment with ZZAP (Adsorption) Treatment with ZZAP (Adsorption) ZZAP effectively rem
58、oves autoantibodies (digestion) allowing ZZAP effectively removes autoantibodies (digestion) allowing more complete absorption of autoantibodies from patients more complete absorption of autoantibodies from patients serum, allowing detection and identification of alloantibody.serum, allowing detecti
59、on and identification of alloantibody.Chemically treated allogenic RBCsChemically treated allogenic RBCs Treated RBCS with proteolytic enzymes, alter some Ags Treated RBCS with proteolytic enzymes, alter some Ags Problems EncounteredWeak or non reacted with any or some cell Weak or non reacted with
60、any or some cell reagent.reagent.Variable reaction Variable reaction Variable expression of Ags (PVariable expression of Ags (P1 1, Lewis), Lewis)Ags deteriorate on storage (Duffy, PAgs deteriorate on storage (Duffy, P1 1, M, Lewis), M, Lewis)Abs is reacting with more than one Ag.Abs is reacting wit
61、h more than one Ag. DDCCee DDCCee 3+3+ Ddccee 1+ Ddccee 1+SolutionUsedoubledoseofcorrespondingAgs,(Rh,Kidd,Duffy,MNS)UsenewcellreagentPost-analytical phasePost-analytical phaseInvolves labeling, inspecting, and issuing the Involves labeling, inspecting, and issuing the blood unitblood unitLabeling f
62、orm includes patients full name, ID Labeling form includes patients full name, ID number, ABO/number, ABO/RhRh of patient and unit, donor #, of patient and unit, donor #, compatibility results, and tech IDcompatibility results, and tech IDForm is attached to the donor unit and only Form is attached
63、to the donor unit and only released for the recipientreleased for the recipientThe unit is visually inspected for abnormalities, The unit is visually inspected for abnormalities, such as bacterial contamination, clots, etcsuch as bacterial contamination, clots, etcBacterial contaminationThis unit sh
64、ows This unit shows bacterial bacterial contamination and contamination and should NOT be given should NOT be given to the patientto the patientThe plasma in the The plasma in the segments is fine, but segments is fine, but the plasma in the unit the plasma in the unit shows heavy shows heavy hemoly
65、sishemolysis from from bacteriabacteriaIssuing bloodWhen its time to release a blood product to the nurse or physician, a few “checks” must be donel lRequisition formRequisition forml lComparing requisition form Comparing requisition form donor unit tag donor unit tag blood product label blood produ
66、ct labell lName of persons issuing and picking up bloodName of persons issuing and picking up bloodl lDate and time of releaseDate and time of releasel lExpiration dateExpiration dateWhat if the unit is unused?Blood can be returned if it is not needed for transfusionUnit closure has to remain unopen
67、edStorage temperature must have remained in the required range (1 to 10C for RBCs)If not at correct temp, unit must be returned within 30 minutes of issueInfusion DeviceBlood WarmerSpecial CircumstancesEmergency ReleaseIn an emergency (ER or OR), there may not be enough time to test the recipients s
68、ampleIn this case, blood is released only when signed by the physician (O negative)The tag must indicate it is not crossmatchedSegments should be retained for X-matchingEvery detail is documented (names, dates.)Emergency ReleaseOnce the specimen is received, ABO/Once the specimen is received, ABO/Rh
69、Rh typing typing and antibody screening should be performedand antibody screening should be performedCrossmatching the segments from the released Crossmatching the segments from the released unit should be testedunit should be testedIn addition, the lab may crossmatch additional In addition, the lab
70、 may crossmatch additional units as a precaution if more blood is neededunits as a precaution if more blood is neededIf death should occur, testing should be complete If death should occur, testing should be complete enough to show that the death was unrelated to enough to show that the death was un
71、related to an incompatibilityan incompatibilityWhat can be given in an emergency?Group O Rh-negative red cells or AB plasmal lEmergency releaseEmergency releasel lWomen below or of childbearing ageWomen below or of childbearing agel lOr if in doubtOr if in doubtGroup O Rh-positive red cellsl lUsed a
72、s a substitutionUsed as a substitutionl lMale or elderly femalesMale or elderly femalesMassive transfusionDefined as a transfusion approaching or Defined as a transfusion approaching or exceeding the recipients own blood volume exceeding the recipients own blood volume (about 5 liters or 10-12 units
73、 in an adult male) (about 5 liters or 10-12 units in an adult male) within 24 hour periodwithin 24 hour periodThe original sample no longer represents the The original sample no longer represents the patients conditionpatients conditionComplete crossmatch not necessary (if no Complete crossmatch not
74、 necessary (if no antibodies were detected originally)antibodies were detected originally)Give ABO identical unitsGive ABO identical unitsl lIf antibodies were originally IDs, continue to give If antibodies were originally IDs, continue to give antigen negative unitsantigen negative unitsAppropriate
75、 units to giveABO compatible should always be given firstPatients Patients TypeType1 1stst Choice ChoiceOther Other ChoicesChoicesOOOONoneNoneA AA AOOB BB BOOABABABABA, B, OA, B, O Group O individuals are “universal donors”, they can donate to any blood group because they have no A or B antigens Gro
76、up AB individuals are “universal recipients”, they can receive blood from any group because they do not have A or B antibodiesRed blood cell compatibility table AB+AB-B+B-A+A-O+O-AB+AB-B+B-A+A-O+O-DonorRecipientPlasmacompatibility tableOBAABABBAODonorRecipientType & ScreenUsed to conserve blood inve
77、ntoryUsed to conserve blood inventoryOn average, a surgical procedure uses about 1 On average, a surgical procedure uses about 1 unit of RBCs, however, many times the units are unit of RBCs, however, many times the units are on “hold” in the lab and will not be needed on “hold” in the lab and will n
78、ot be needed (reducing inventory)(reducing inventory)For this reason, only a type & screen are For this reason, only a type & screen are performed and if any blood is needed, the performed and if any blood is needed, the sample can be retrieved for crossmatching (only sample can be retrieved for cro
79、ssmatching (only the IS phase is required)the IS phase is required)If antibodies If antibodies areare identified, then antigen negative identified, then antigen negative blood is reserved or crossmatchedblood is reserved or crossmatchedNeonatal TransfusionA neonate who is A neonate who is 4 months4
80、months old does not have old does not have antibodiesantibodiesABO/ABO/RhRh compatible blood is given compatible blood is givenHowever, if clinically significant antibodies are However, if clinically significant antibodies are detected, they are usually maternal and antigen detected, they are usuall
81、y maternal and antigen negative units are givennegative units are givenEither Either infant or maternal seruminfant or maternal serum can be used can be used for the crossmatchfor the crossmatchPedipacksPedipacks are small aliquots of larger units and are small aliquots of larger units and prepared
82、by the donor facility or hospital lab for prepared by the donor facility or hospital lab for infant transfusioninfant transfusionAutologous crossmatchingAutologous refers to a donation from the recipient for later useSpecial procedures/protocols must be available so that the autologous unit is found
83、 and transfused to the recipientPretransfusion testing procedures varyOther componentsOther components to be given do not need to be crossmatched because they have been thoroughly screened for antibodiesl lFrozen plasmaFrozen plasmal lPlatelet concentratePlatelet concentratel lCryoprecipitateCryopre
84、cipitatel lPlatelets pheresisPlatelets pheresisl lGranulocyte concentratesGranulocyte concentratesGive ABO compatible unitsNew TechnologiesThe electronic crossmatchAccording to the AABB, the following must be fulfilled:l lCritical elements of the information system Critical elements of the informati
85、on system have been validated on-site. have been validated on-site. l lNo clinically significant antibodies are No clinically significant antibodies are detected in the current blood sample and detected in the current blood sample and there is no record of clinically significant there is no record o
86、f clinically significant antibodies in the pastantibodies in the pastComputer crossmatch (contd)The patients ABO group and Rh type has been The patients ABO group and Rh type has been done twice and entered in the computerdone twice and entered in the computerThe donor ABO/The donor ABO/RhRh have be
87、en confirmed and have been confirmed and entered in the computer. The donor unit entered in the computer. The donor unit identification number, component name, and identification number, component name, and ABO/ABO/RhRh type must also be entered in the type must also be entered in the computer compu
88、ter The computer system will alert the technologist The computer system will alert the technologist to ABO & Rh discrepancies between information to ABO & Rh discrepancies between information on the donor label and results of donor on the donor label and results of donor confirmatory testing confirmatory testing June, 1938
