Antiphospholipid Syndrome
(APS)

Sample type:

Plasma, frozen; and serum, room temperature.

Test use:

Antiphospholipid antibodies are a group of immune proteins (antibodies) that the body mistakenly produces against itself in an autoimmune response to phospholipids. Tests can detect these autoantibodies that bind to phospholipids and, in a way that is not well understood, increase the risk of excessive blood clotting.

Precautions:

Ideally, the patient should not be on anticoagulant therapy. Avoid warfarin (Coumadin®) therapy for two weeks prior to the test and heparin, direct Xa, and thrombin inhibitor therapies for about three days prior to testing.

Interfering factors:

Test done for syphilis can cause a false-positive antiphospholipid antibody test result if done at the same time. That’s because the substances used to test for syphilis have phospholipids in them. You may need a second test to confirm the results.

Pre analytical errors:

Severe hemolysis; improper labeling; clotted specimen; specimen diluted with IV fluids; samples thawed in transit; improper sample type; sample out of stability

Post analytical errors:

1) Delayed report.

2) You may be instructed not to eat (fast) six hours before the test.

Corrective actions:

1) If the dilute Russell viper venom time (dRVVT) screen is high, a confirmation test will be performed.

2) If thrombin time is greater than 30.0 seconds, thrombin neutralization will be performed.

3) If activated partial thromboplastin time (aPTT) is 3 or more seconds above the upper limit of the reference range, activated partial thromboplastin time 1:1 normal plasma will be performed.