Laboratory Medicine Program
Anti-phospholipid Antibody Panel (APA)
(Lupus Anticoagulant, dRVVT/APLA)
Clinical Decription:
The laboratory identification of anti-phopholipid antibodies (APAs) requires a minimum of three test components including the anti-cardiolipin antibody ELISA assay (ACA), and at least two clotting assays for identification of phospholipid-dependent inhibitors (generally the dilute Russell Viper Venom Time and the lupus sensitive aPTT). APAs are found in association with connective tissue disorders, venous or arterial thrombosis, thrombocytopenia and recurrent fetal loss but are also commonly identified in >2% of the general population. An abnormality of any one of these three test components is interpreted as positive for the presence of APAs. Since APAs may be transient phenomena this test should be repeated at 3 months to confirm antibody persistence.
<br/><em>Pengo V,Tripodi A, Reber G, Rand JH, Ortel TL, Galli M, DeGroot PG. Update of the Guidelines for Lupus Anticoagulant Detection; J Thromb Haemost 2009 Oct 7 (10) pg 1737-40.</em>
Method: Optical Clot Detection; Siemens Sysmex CS-5100
Component Tests Used: Dilute Russell Viper Venom Time, Lupus-sensitive aPTT, Anti-cardiolipin Antibodies
Reference Ranges Used:
dRVVT ratio < 1.35 Medical Interpretation is provided.
Specimen Type: Citrated plasma
Collected In: 3.2% Sodium Citrate
Volume: 3 x 1.0 mL (minimum: 3 x 1.0 mL)
Shipping: Send frozen on dry ice.
Special Instructions: Patient should be fasting, if possible. Anticoagulants should be held for a requisite amount of time prior to testing to ensure no anticoagulant effect on the plasma. The specimen must be double-centrifuged to obtain a platelet-poor plasma specimen (Plt < 10x10E9/L): 1. Immediately centrifuge specimen at 1500xG for 10 minutes. 2. Separate the plasma from the platelet/buffy coat and transfer into a clean plastic tube. 3. Centrifuge the separated plasma at 1500xG for 10 minutes. 4. Transfer 1.0 to 2.0 mL of the double-centrifuged plasma into a clean plastic tube, leaving approx. 200 uL for discard. 5. Freeze plasma aliquot immediately for storage. Maintain frozen for shipping and handling. Patients on warfarin may give a false positive result. Patients receiving a Direct Thrombin Inhibitor such as Dabigatran cannot be tested for the Antiphospholipid Antibody as the anticoagulant interferes with the clotting assays.
Testing Schedule(s): Weekly.
Turnaround Time: 10 Business days
For more information, call 416.340.5227 or 1.866.865.5227