Pretransfusion Testing Flashcards
Purpose of pretransfusion compatibility testing
Ensures patient safety by matching compatible blood.
Steps in pretransfusion testing
Identify and handle recipient and donor blood.
Specimen collection requirements
Label with full name, ID, and collection date.
Acceptable specimen types
Anticoagulated or clotted samples; serum in plain tubes.
Unacceptable specimen conditions
Hemolysis or IV contamination causes positive results.
Specimen retention post transfusion
Retain for at least 7 days.
Effect of lipemia
Lipemia usually does not lead to rejection.
Tests performed
ABO typing, Rh typing, AB screening, and antibody ID.
Recipient blood selection (AB) first to least choice
AB can receive from AB, A, B, O.
Recipient blood selection (A) first to least choice
A can receive from A, O.
Recipient blood selection (B) first to least choice
B can receive from B, O.
Recipient blood selection (O) first to least choice
O can only receive from O.
Crossmatching purpose
Final check of ABO compatibility and detection of undetected antibodies.
Serologic major crossmatch test procedure
Patient serum tested with donor RBC (Immediate spin, thermal phase, AHG).
Reasons for crossmatch incompatibilities
Incorrect ABO grouping, undetected cold-reactive antibodies, plasma abnormalities.
Crossmatch with negative antibody screen
Immediate spin if no clinically significant antibody is detected.
Type and screen request with negative antibody screen
ABO/D phenotype determined; no alloantibodies means no further testing needed.
Crossmatch procedure with detected alloantibody
Complete crossmatch (immediate spin + antiglobulin) with antigen-negative units.
Previous alloantibody and crossmatch procedure
Perform complete crossmatch (immediate spin + antiglobulin) on antigen-negative units for prior and new antibodies.
Computer crossmatch use
Only for patients with no clinically significant antibodies or history of alloantibodies.
Computer crossmatch function
Compares ABO serologic results and interpretation.
Advantages of computer crossmatch
Increased efficiency, reduced sample volume, flexibility, potential cost savings, and centralized transfusion service.
Incompatible crossmatch with positive AHG (One antibody screening cell and one donor positive in AHG)
Likely alloantibody.
Resolution for incompatible crossmatch with alloantibody
Identify the antibody and crossmatch units negative for the corresponding antigen.
Incompatible crossmatch with positive DAT on donor (Antibody screening cells and autocontrol negative; one donor positive in AHG)
Likely positive DAT on donor.
Resolution for positive DAT on donor
Return the unit to the blood collecting facility.
Incompatible crossmatch with warm autoantibody (Antibody screening cells, donors, and autocontrol positive in AHG)
Likely warm autoantibody.
Resolution for warm autoantibody
Avoid transfusion if possible; if necessary, find the least incompatible unit.
Incompatible crossmatch with rouleaux (Antibody screening cells, donors, and autocontrol positive at 37°C, negative in AHG)
Likely rouleaux formation.
Resolution for rouleaux
Use saline replacement technique.
Unused unit requirements
Unit closure must remain unopened; storage temperature 1-10°C for RBCs; if not, return within 30 minutes of issue.
Neonatal transfusion criteria
Less than 7 days old; CMV negative or leukocyte reduced; O-negative; Hemoglobin S negative; Dose: 10 ml/kg over 2-3 hours.
Autologous transfusion benefit
Reduces the risk of transfusion reactions and transmission of infectious diseases.
Emergency transfusion criteria
Transfusion of RBC components before completion of pretransfusion testing: ABO specific blood, O Rh negative, or O Rh positive for males and females above childbearing age.
Not required for compatibility testing of blood components
Plasma products, platelets, thawed plasma, or cryoprecipitate.
Massive transfusion complications
Citrate toxicity (calcium hypo), iron overload, bleeding.
