Pretransfusion Testing

Question 1

Purpose of pretransfusion compatibility testing

Answer 1

Ensures patient safety by matching compatible blood.

Question 2

Steps in pretransfusion testing

Answer 2

Identify and handle recipient and donor blood.

Question 3

Specimen collection requirements

Answer 3

Label with full name, ID, and collection date.

Question 4

Acceptable specimen types

Answer 4

Anticoagulated or clotted samples; serum in plain tubes.

Question 5

Unacceptable specimen conditions

Answer 5

Hemolysis or IV contamination causes positive results.

Question 6

Specimen retention post transfusion

Answer 6

Retain for at least 7 days.

Question 7

Effect of lipemia

Answer 7

Lipemia usually does not lead to rejection.

Question 8

Tests performed

Answer 8

ABO typing, Rh typing, AB screening, and antibody ID.

Question 9

Recipient blood selection (AB) first to least choice

Answer 9

AB can receive from AB, A, B, O.

Question 10

Recipient blood selection (A) first to least choice

Answer 10

A can receive from A, O.

Question 11

Recipient blood selection (B) first to least choice

Answer 11

B can receive from B, O.

Question 12

Recipient blood selection (O) first to least choice

Answer 12

O can only receive from O.

Question 13

Crossmatching purpose

Answer 13

Final check of ABO compatibility and detection of undetected antibodies.

Question 14

Serologic major crossmatch test procedure

Answer 14

Patient serum tested with donor RBC (Immediate spin, thermal phase, AHG).

Question 15

Reasons for crossmatch incompatibilities

Answer 15

Incorrect ABO grouping, undetected cold-reactive antibodies, plasma abnormalities.

Question 16

Crossmatch with negative antibody screen

Answer 16

Immediate spin if no clinically significant antibody is detected.

Question 17

Type and screen request with negative antibody screen

Answer 17

ABO/D phenotype determined; no alloantibodies means no further testing needed.

Question 18

Crossmatch procedure with detected alloantibody

Answer 18

Complete crossmatch (immediate spin + antiglobulin) with antigen-negative units.

Question 19

Previous alloantibody and crossmatch procedure

Answer 19

Perform complete crossmatch (immediate spin + antiglobulin) on antigen-negative units for prior and new antibodies.

Question 20

Computer crossmatch use

Answer 20

Only for patients with no clinically significant antibodies or history of alloantibodies.

Question 21

Computer crossmatch function

Answer 21

Compares ABO serologic results and interpretation.

Question 22

Advantages of computer crossmatch

Answer 22

Increased efficiency, reduced sample volume, flexibility, potential cost savings, and centralized transfusion service.

Question 23

Incompatible crossmatch with positive AHG (One antibody screening cell and one donor positive in AHG)

Answer 23

Likely alloantibody.

Question 24

Resolution for incompatible crossmatch with alloantibody

Answer 24

Identify the antibody and crossmatch units negative for the corresponding antigen.

Question 25

Incompatible crossmatch with positive DAT on donor (Antibody screening cells and autocontrol negative; one donor positive in AHG)

Answer 25

Likely positive DAT on donor.

Question 26

Resolution for positive DAT on donor

Answer 26

Return the unit to the blood collecting facility.

Question 27

Incompatible crossmatch with warm autoantibody (Antibody screening cells, donors, and autocontrol positive in AHG)

Answer 27

Likely warm autoantibody.

Question 28

Resolution for warm autoantibody

Answer 28

Avoid transfusion if possible; if necessary, find the least incompatible unit.

Question 29

Incompatible crossmatch with rouleaux (Antibody screening cells, donors, and autocontrol positive at 37°C, negative in AHG)

Answer 29

Likely rouleaux formation.

Question 30

Resolution for rouleaux

Answer 30

Use saline replacement technique.

Question 31

Unused unit requirements

Answer 31

Unit closure must remain unopened; storage temperature 1-10°C for RBCs; if not, return within 30 minutes of issue.

Question 32

Neonatal transfusion criteria

Answer 32

Less than 7 days old; CMV negative or leukocyte reduced; O-negative; Hemoglobin S negative; Dose: 10 ml/kg over 2-3 hours.

Question 33

Autologous transfusion benefit

Answer 33

Reduces the risk of transfusion reactions and transmission of infectious diseases.

Question 34

Emergency transfusion criteria

Answer 34

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.

Question 35

Not required for compatibility testing of blood components

Answer 35

Plasma products, platelets, thawed plasma, or cryoprecipitate.

Question 36

Massive transfusion complications

Answer 36

Citrate toxicity (calcium hypo), iron overload, bleeding.