Compatibility Testing Flashcards by Kyra Catedral

COMPATIBILITY TESTING?
• Also called…

pretransfusion testing

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Purpose of compatibility testing

• To select blood components that will not cause harm to the recipient and will have acceptable survival when transfused

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• If properly performed, compatibility tests will confirm______ between the component and the recipient and will detect the most clinically significant unexpected antibodies

ABO compatibility

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•There are several components of compatibility testing (5)

• Proper specimen collection
• Reviewing patient transfusion history
• ABO, Rh, and antibody testing (screen/ID)
• Crossmatching
• Actual transfusion

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PRE-ANALYTICAL PHASES (3)

•Patient identification
•Specimen collection
•Review of patient history

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PATIENT IDENTIFICATION
• Must confirm recipient’s ID from______
(+ 2)

bracelet ON the patient

•Full patient name and hospital number
•Name of physician

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SAMPLE IDENTIFICATION
• The sample should also have the ____,_____,_____
• ______ and ______

• All of this should be on the request form and the sample

full patient name,
hospital number, and
physician

Date and time of collection, phlebotomist’s initials

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SPECIMEN TUBES (2)

Pink Top - EDTA
Red Top - no additives

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SPECIMEN COLLECTION
• Collected in tube with____ or ____
• If the venipuncture causes hemolysis, the sample may be____
•True hemolysis in the patient is the result of_____

EDTA or no additives

rejected

complement activation

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SPECIMEN COLLECTION

•Samples are labeled_____
• A record of_____

at the bedside (pre-labeling is not recommended)

individuals who collect (or test) the specimens should be documented in order to “backtrack” in case of an error

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SPECIMEN COLLECTION

•If the sample is drawn from an IV line, the IV infusion should be stopped______ prior to blood drawing and the _____discarded

5-10 minutes

first 10 mL

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SPECIMEN COLLECTION

•Testing should be performed on samples______ or else complement dependent antibodies may be missed (complement can become unstable)

less than 72 hours

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Getting the history
•Look at_____ records for any prior unexpected antibodies
•Previous transfusion reactions

recipient’s

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Serological testing

•3 tests:

•ABO/Rh
•Antibody detection/identification
•Crossmatch

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ABO/Rh typing
•In the ABO typing,_____ and _____ MUST match

the forward and reverse

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ABO/ Rh Typing

• In the Rh typing, the control must be_____

negative

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will detect the presence of any unexpected antibodies in patient serum

•The antibody screen

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• If antibodies are detected, identification should be performed using panel cells (with an autocontrol)

(3)

• Immediate spin
• 37° (LISS)
• AHG

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Antibody screen

•If an antibody is present, units______ for the antigen must be given
•Proceed to the______…

negative

crossmatch

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Crossmatching
•Purpose: (4)

• Prevent transfusion reactions
• Increase in vivo survival of red cells
• Double checks for ABO errors
• Another method of detecting antibodies

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•Two types of crossmatches
•_____
routinely performed in labs
•_____
•not required by AABB since
1976

Major

Minor

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•Why is the minor crossmatch
unnecessary?

•Donated units are tested for antibodies
•Most blood is transfused as packed cells, having little antibodies

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CROSSMATCHES
•The (2) develop the standards for blood banking

AABB and FDA

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According to the AABB Standards: The____ "shall use methods that demonstrate ABO incompatibility and clinically significant antibodies to red cell antigens and shall include an antiglobulin phase"

crossmatch

CROSSMATCH Components for Major Crossmatching? (3) No agglutination -______ Agglutination -_____

Patient serum + Donor RBCs (washed) compatible incompatible

THE PROCEDURE •Donor cells are taken from_____ that are attached to the unit itself •These are a sampling of the blood and eliminate having to open the actual unit

segments

PROCEDURE •______ is FIRST performed •______is performed next... •if antibodies are ***NOT DETECTED:*** •_______ is performed using patient serum and donor blood suspension •This fulfills the AABB standard for ABO incompatibility •This is an INCOMPLETE CROSSMATCH •If antibodies ***ARE DETECTED:*** •Antigen negative units found and X-matched •______ are tested • This is a COMPLETE CROSSMAT CH

ABO/Rh typing Antibody Screen Only immediate spin (IS) All phases are tested: IS, 37°, AHG

ABO/D phenotype determined ***No alloantibodies detected***

• No further testing needed • Perform immediate- spin or computer crossmatch if units are ordered

ABO/D phenotype determined ***Alloantibody detected***

• Identify antibody • Perform a complote crossmatch (immediate-spin and antiglobulin) on units that are antigon-negalivo for antibody

ABO/D phenotype determined ***Record of previous alloantibody***

• Rule out or identity additional antibodies • Perform immediate-spin and antiglobulin cross-match on units that aro aniligon-negative for prior and now alloantibody

CROSSMATCHES Will (2)

Verify donor cell ABO compatibility Detect most antibodies against donor cells

CROSSMATCHES WILL NOT (5)

Guarantee normal survival of RBCs Prevent patient from developing an antibody Detect all antibodies Prevent delayed transtusion reactions Detect ABO/Rh errors

Antibody screen - Pos Crossmatch - Neg Cause Resolution

Antibody directed against antigen on screening cell ID antibody, select antigen negative blood

Antibody screen - Neg Crossmatch - Pos Cause Resolution

Antibody directed against antigen on donor cell which may not be on screening cell OR donor unit may have IgG previously attached ID antibody, select antigen negative blood OR perform DAT on donor unit

Antibody screen - Pos Crossmatch - Pos Cause Resolution

Antibodies directed against both screening and donor cells Antibody ID, select antigen negative blood

Additional information on types of compatibility tests

•Manual (IS and IAT) •Gel Technology •Electronic (Computerized) Cross match •Red cell Affinity Column Technology (ReACT) • Solid Phase Adherence Assays (SPAA)

MANUAL (IS AND IAT) ANTIBODY (2) types

Naturally occurring Acquired

2 types of acquired antibody

Alloantibody Autoantibody

Immediate Spin detect…

RT reactive antibodies (Auto, Alloantibody, Naturally occuring)

IAT detect…

IgG antibodies (Auto & alloantibody)

GEL TECHNOLOGY • Patient serum, and 1% of suspended RBCs in LIM are dispensed into the microtube and incubated at 37°C for 15 minutes. • The card containing the microtubes is then centrifuged at a controlled speed for 10 minutes. • At the start of centrifugation the cells are separated from the serum; then they meet the AHG contained in the microtube. • Finally the cells are trapped by the gel (i agglutinated) or pellet to the bottom of the tube.

PHASE PURPOSE: detection IgM cold agglutinin DETECTS: Most ABO incompatibilities

PHASE PURPOSE: IgG Abs DETECTS: Potent Rh Abs

37°C, LISS

PHASE PURPOSE: IgG Abs DETECTS: Rh, Duffy, Kidd, others

AHG

PHASE PURPOSE: AHG absence, inadequacy, or neutralization DETECTS: Sensitized RBCs

OCC

***Limitations of pretransfusion testing*** • Hemolytic transfusion reaction, if the patient's antibody is…. • standard antibody detection methods such as the indirect antiglobulin test require several____ molecules per red cell to produce detectable reactions. • A hemolytic transfusion reaction due to_______. For example, group A red cells (meant for transfusion to a group O recipient) will be compatible in vitro tests with an incorrect specimen drawn from a group A person.

too weak to be detected. 100 antibody patient misidentification

**¥Limitations of pretransfusion testing*** • Hemolytic transfusion reaction if donor red cells are_______ before entering the patient, e.g., red cells hemolysed by an improperly functioning blood warmer or red cells hemolysed by contact with an ice pack in a transport container. •Nonhemolytic transfusion reactions such as______ •Pretransfusion test are meant to detect only______

inadvertently hemolysed allergic, rebrile, and other reactions. red cell antibodies.

Incompatible crossmatch • ABO incompatibility • Recheck patient and blood unit ABO group • Clinically Significant Antibody • DAT & LAT

Post-analytical phase • Involves_____, ____and _____

labeling, inspecting, and issuing the blood unit

Post Analytical Phase • Labeling form includes (6) PIADCT •The unit is visually inspected for abnormalities, such as…

patient's full name, ID number, ABO/Rh patient and unit, donor #, compatibility results, and tech ID bacterial contamination, clots, etc

Post-Analytical Phase *m is attached to the donor unit and only released for the recipient?????

Issuing blood • When it's time to release a blood product to the______ or _____, a few "checks" must be done •_______ • Comparing_____ →______ →______ •_______ •_______ •_______

nurse or physician Requisition form requisition form > donor unit tag > blood product label Name of persons issuing and picking up blood Date and time of release Expiration date

What if the unit is unused? •Blood can be returned if it is not needed for transfusion • Unit closure has to remain unopened •Storage temperature must have remained in the required range (_______for RBCs) •If not at correct temp, unit must be returned_____ of issue

1° to 10°C within 30 minutes

T or F •Blood can be returned if it is not needed for transfusion

True

EMERGENCY RELEASE •In an emergency (ER or OR), there may not be enough time to test the recipient's sample •In this case, blood is released only when________ •The tag must indicate it is______ •Segments should be retained for_____ •Every detail is documented (names, dates..)

signed by the physician (O negative) not crossmatched X-matching

What can be given in an emergency? • Emergency release • Women below or of childbearing age • Or if in doubt

Group O Rh-negative red cells or AB plasma

What can be given in an emergency? • Used as a substitution • Male or elderly females

Group O Rh-positive red cells

•Defined as a transfusion approaching or exceeding the recipient's own blood volume

Massive Transfusion

Massive Transfusion •Defined as a transfusion approaching or exceeding the recipient's own blood volume (about_____ or _____ in an adult male) within_____ period • The original sample no longer represents the patient's condition • _____not necessary (if no antibodies were detected originally) • Give_____ units • lf antibodies were identified, continue to give antigen negative units

5 liters or 10-12 units; 24 hour Complete crossmatch ABO identical units

• Used to conserve blood inventory

TYPE & SCREEN

• On average, a surgical procedure uses about____ unit of RBCs, however, many times the units are on "hold" in the lab and will not be needed (reducing inventory) • For this reason, only a _____are performed and if any blood is needed, the sample can be retrieved for_____ (only the IS phase is required) •lf antibodies are identified, then antigen negative blood is reserved or crossmatched

1 type & screen crossmatching

Neonatal Transfusion •A neonate who ______ old does not have_____ •______blood is given •However, if clinically significant antibodies are detected, they are usually maternal and antigen negative units are given • Either ______ or _____can be used for the crossmatch

is <4 months old ; antibodies ABO/Rh compatible infant or maternal serum

• are small aliquots of larger units and prepared by the donor facility or hospital lab for infant transfusion

Pedipacks

refers to a donation from the recipient for later use •Special procedures/protocols must be available so that the unit is found and transfused to the recipient •Pretransfusion testing procedures vary

Autologous Crossmatching

Other Components • Other components to be given do not need to be crossmatched because they have been thoroughly screened for antibodies (5) • Give____ compatible units

• Frozen plasma • Platelet concentrate • Cryoprecipitate • Platelet apheresis • Granulocyte concentrates ABO

New Technologies • The______ •According to the AABB, the following must be fulfilled: • Critical elements of the information system have been validated on-site. • No clinically significant antibodies are detected in the current blood sample and there is no record of clinically significant antibodies in the past

electronic crossmatch

Computer Crossmatch • The patient's_____ and _____ has been done twice and entered in the computer • The donor ABO/Rh have been confirmed and entered in the computer. The donor unit identification number, component name, and ABO/Rh type must also be entered in the computer •The computer system will alert the technologist to ABO & Rh discrepancies between information on the donor label and results of donor confirmatory testing

ABO group and Rh type