Eluate of anti-erythrocyte antibodies

Clinical information

Diagnostic Utility:

This test consists of eluting antibodies bound to red blood cells and investigating their specificity. It is useful in cases of a positive direct antiglobulin test for IgG, in the context of:

• Autoimmune hemolytic anaemia (AIHA).
• Drug-induced hemolytic anaemia.
• Hemolytic transfusion reactions.
• Maternal-fetal incompatibility and hemolytic disease of the fetus and newborn (HDFN).

Method: 

In the case of autoimmune hemolytic anaemia, a commercial acid elution is used.

In the case of ABO maternal-fetal incompatibility, the Lui method (cold elution) may be added when the standard method (acid elution) has not yielded the expected result.

Reference Values

Normal red blood cells do not have antibodies covering them. If antibodies bound to red blood cells are detected, this test allows for their elution. The result is therefore negative or positive.

In some cases of AIHA, the autoantibody may have a relative specificity and in these cases, it is indicated, for example, autoanti-e.

In the case of HDFN, when the eluate is positive, a certain specificity is always found, which is also indicated, for example: anti-A, anti-D.

Diagnostic Algorithm:

In the case of AIHA or a hemolytic reaction, this test 0014 is generated when test 9993 Direct Coombs differential has tested positive for IgG. Even if only 0014 is requested, the laboratory needs to know that the sample has a positive direct Coombs for IgG. That is why a Direct Coombs differential will always be performed initially.

In the case of HDFN, the Eluate is part of a broader study of maternal-fetal incompatibility that includes the mother and baby's ABO/RhD group, an irregular antibody screening in the mother, and the direct antiglobulin test in the baby.

Turnaround Time:

1 day when identification is unequivocal.
Several days may be required when identification is complex (mixtures of antibodies or uncommon specificities).

Specimen information

Sample: Whole blood
Tube: EDTA K3 10 ml tube
Minimum volume: 6 ml (1 ml in infants)
Stability:

• At room temperature: 2 days
• In refrigeration: 2 days

Transport instructions: Preferably at room temperature
Reason for rejection: Highly hemolyzed sample

Administrative information

BST Code: 0014
Test Description: Anti-erythrocyte antibody eluate
Synonyms: Not applicable
Section: Immunohematology
BST Rate: Check updated rates by clicking here.

Profiles:

Test 0014 Anti-erythrocyte antibody eluate can be requested individually. It is also performed within the following profiles:

References

AABB Technical Manual. 19th edition. Editat per MK Fung, AF Eder, SL Spitalnik, CM Westhoff: AABB 2017