Direct Antiglobulin Test
(DAT)

Sample type

For (DAT) Whole blood (EDTA)

Use

The DAT is used whenever hemolysis of red cells is suspected as being caused by autoantibodies. The assay determines if red cells have been coated in vivo with immunoglobulins, complement, or both.

Precautions

The DAT is reported and interpreted as either positive or negative

The DAT is positive whenever the patient’s red cells are coated with autoantibodies that developed against the patient’s own red cells. It is also positive when alloantibodies in a recipient’s circulation react with antigens on recently transfused red cells, as well as alloantibodies in maternal circulation, which cross the placenta and coat fetal red cells.

Antibodies directed against certain drugs may also bind to red cell membranes and result in a positive test.

Interfering factors

A negative DAT does not rule out hemolysis but only hemolysis of autoimmune etiology. For instance, DAT is negative in some cases of drug-induced hemolytic anemias, hemoglobinopathies, hereditary spherocytosis, and other hereditary hemolytic anemias.

Pre analytical errors

1- Incorrect Analysis ordered

2- patients identification error

3- sample collection errors

Corrective action

1- Using appropriate technology.

2- Monitoring quality indicators in the lab.

3- Choosing appropriate products.

Post analytical errors

1- Report delayed

2- Not all requested tests done

3- Sharing the results of patients or writing the result incorrectly.

Corrective action

1- Done Accurate Reports after doing tests

2- Assure that the prescribed preventive maintenance for the instruments is performed

3- Attention when delivered the results of patient and write them in the reports

Reference Range

Normal findings: Negative; no agglutination