Lupus anticoagulant (LA) screen
| Category | Haematology >> Specialised Coagulation Services |
|---|---|
| Test background |
LA is a group of antibodies found in patients with SLE, as well as other autoimmune disorders and recurrent fetal loss. Although associated with thrombotic events, it may be characterised by a prolonged APTT, due to an in vitro anticoagulant effect (in contrast to the prothrombotic in vivo effect). Screening for lupus anticoagulant is performed as part of the screen for antiphospholipid syndrome and should therefore be performed in conjunction with a cardiolipin antibody test. See Cardiolipin antibodies, Immunology. |
| Clinical Indications |
Unexplained arterial or venous thrombosis Venous thromboembolism at a young age (including childhood) Recurrent venous thromboembolism Unusual site of thrombosis (eg. mesenteric, renal, portal veins, cerebral venous sinuses) Thrombosis during pregnancy or puerperium Recurrent superficial thrombophlebitis Arterial thrombosis at a young age (abruptio placentae, pre-term delivery) Neonatal purpura fulminars or massive thrombosis in newborn |
| Sample & container required | 3 x 4.5 mL sodium citrate (pale blue top) |
| Turnaround time | 14 days |
| Notes | Special handling: avoid prolonged stasis during venepuncture. Sample must be received by lab within 2 hours of collection. Please note: samples will be rejected if underfilled, clotted or haemolysed, or if they come from patients receiving anticoagulant therapy. Similarly, sampling is inappropriate within 4 weeks post-childbirth, or during an acute phase inflammatory response. |