PTD - 6

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Test Directory -  Direct Antiglobulin Test

Synonyms

DAGT, DCT, DAT, Direct Coomb's Test, Coomb's Test

Clinical Indications

Laboratory screening results suggest follow up test and/or Consultant direction. Examples; haemolytic anaemia, possible transfusion reaction, haemolysis screen. Cord specimens NO LONGER require a DAGT test as part of the Cord & Maternal Testing.

Request Form 

Combined Pathology Blood form (Yellow/Black or Blue for GP's)

Availability

On request.

Specific Criteria

On clinical indication only with guidance from Consultant Haematologist

Turnaround Time

Same Day

Specimen

 Whole Blood

Volume

1 x 3 ml or 1 ml if neonatal patient

Container

Purple top (EDTA) tube

Paediatric 1 ml Red top bottles acceptable for neonates

Collection

Samples must be labelled in full and signed by person collecting the blood, in accordance with the Blood Transfusion specimen acceptance policy. Samples must be transported to the laboratory immediately.

Lab. Handling

Samples are spun before processing.

Causes for Rejection

Unlabelled samples. Incorrect or inadequate patient identifiers provided. Insufficient sample volume, poor sample quality due to deterioration, haemolysis, presence of clot.

Limitations

False-positive or false-negative test results can occur from bacterial or chemical contamination of test materials, improper centrifugation or improper storage of materials.
Anomalous results may be caused by fresh serum or fibrin or particulate matter in plasma.

Not all positive reactions imply the presence of clinically significant antibodies. To further investigate positive results elution techniques may be used.

Reference Range

Refer to individual reports.

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Version 1.0 / December 2012