Test Directory

This test is intended for the detection and semi-quantitation of IgG anti-prothrombin (aPT) antibodies. Antiphospholipid antibodies are a heterogenous group of antibodies that bind to protein-phospholipid complexes. aPT antibodies are included in this category and may be detected in patients with autoimmune diseases (e.g. systemic lupus erythematosus) and/or with antiphospholipid syndrome (APS). The aPT antibody concentration values obtained from this assay are an aid to diagnosis only.

Preferred Specimen Type: Citrated Plasma

Alternate Specimen Type: Serum

Preferred Collection Container: Light Blue Top (Sodium Citrate)

Alternate Collection Container: Gold Top, Serum Separator

Desired Specimen Volume: 0.5 mL

1. Collect a light blue top (sodium citrate) tube via venipuncture.

Platelet-Poor Plasma Processing Instructions

1. Perform platelet poor plasma processing procedure.
2. Transfer 0.5 mL of platelet poor plasma to a clear aliquot tube (screw cap).

Transport to the laboratory frozen.

• Gross hemolysis

See patient report.

If the results from this test are negative, and the clinical history is suggestive of APS, suggest testing for the APS criteria antibodies - IgG and IgM beta-2-glycoprotein I and cardiolipin antibodies, and lupus anticoagulant. If the latter testing is positive, it is recommended to repeat testing in at least 12 weeks to demonstrate persistence of antibodies.