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Print CPT 85613; 85732. If reflex testing is performed, concomitant CPT codes/charges will apply.
Synonyms
- Lupus Anticoagulant
- Lupus Anticoagulant Screen
Test Details
Turnaround Time
2 - 3 days
Use
This test is used for qualitative detection of lupus anticoagulants in plasma.6
Methodology
PTT-LA (lupus-sensitive aPTT) and dRVVT screen; mixing study if screening tests are prolonged; confirmation if the mixing studies do not correct
Related Documents
For more information, please view the literature below.
Procedures for Hemostasis and Thrombosis: A Clinical Test Compendium
Additional Information
Lupus anticoagulants are nonspecific antibodies that extend the clotting time of phospholipid-dependent clotting assays such as the aPTT.6,7 Unlike specific factor antibodies, LA are usually associated with venous thrombosis, pulmonary embolism, arterial thrombosis, and recurrent fetal loss.8 LA do not specifically inhibit individual coagulation factors; rather they neutralize anionic phospholipid-protein complexes that are involved in the coagulation process. Prolongation of clot-based assays is highly dependent on the sensitivity of the reagent employed. Reagents with reduced amounts of phospholipid, such as the aPTT-LA and dilute Russell viper venom time (dRVVT), have enhanced sensitivity for LA.6 Due to the heterogeneity of LA antibodies, no single assay will identify all cases.8 The International Society on Thrombosis and Haemostasis (ISTH) has established criteria for the diagnosis of lupus anticoagulants.6-8 Testing for lupus anticoagulant (LA) and the antiphospholipid syndrome that is associated with these antibodies is described in more detail in the online Coagulation Appendices: Lupus Anticoagulants and Antiphospholipid Syndrome.
Specimen Requirements
Information on collection, storage, and volume
Specimen
Plasma, frozen
Volume
2 mL
Minimum Volume
1 mL (Note: This volume does not allow for repeat testing.)
Container
Blue-top (sodium citrate) tube
Storage Instructions
Freeze.
Causes for Rejection
Severe hemolysis; improper labeling; clotted specimen; specimen diluted with IV fluids; samples thawed in transit; improper sample type; sample out of stability
Collection
Citrated plasma samples should be collected by double centrifugation. Blood should be collected in a blue-top tube containing 3.2% buffered sodium citrate.1 Evacuated collection tubes must be filled to completion to ensure a proper blood to anticoagulant ratio.2,3 The sample should be mixed immediately by gentle inversion at least six times to ensure adequate mixing of the anticoagulant with the blood. A discard tube is not required prior to collection of coagulation samples.4,5 When noncitrate tubes are collected for other tests, collect sterile and nonadditive (red-top) tubes prior to citrate (blue-top) tubes. Any tube containing an alternate anticoagulant should be collected after the blue-top tube. Gel-barrier tubes and serum tubes with clot initiators should also be collected after the citrate tubes. Centrifuge for 10 minutes and carefully remove 2/3 of the plasma using a plastic transfer pipette, being careful not to disturb the cells. Deliver to a plastic transport tube, cap, and recentrifuge for 10 minutes. Use a second plastic pipette to remove the plasma, staying clear of the platelets at the bottom of the tube. Transfer the plasma into a Labcorp PP transpak frozen purple tube with screw cap (Labcorp No. 49482). Freeze immediately and maintain frozen until tested.
Please print and use the Volume Guide for Coagulation Testing to ensure proper draw volume.