Lupus Anticoagulant With Reflex*

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Turnaround Time: 2 - 3 days
CPT Code:

85613; 85732. If reflex testing is performed, concomitant CPT codes/charges will apply.

Test Type: 2 mL Plasma, frozen

Overview:

Qualitative detection of lupus anticoagulants in plasma6.

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.

1. Adcock DM, Kressin DC, Marlar RA. Effect of 3.2% vs 3.8% sodium citrate concentration on routine coagulation testing. Am J Clin Pathol. 1997; 107(1):105-110. PubMed 8980376

2. Reneke J, Etzell J, Leslie S, et al. Prolonged prothrombin time and activated partial thromboplastin time due to underfilled specimen tubes with 109 mmol/L (3.2%) citrate anticoagulant. Am J Clin Pathol. 1998; 109(6):754-757. PubMed 9620035

3. National Committee for Clinical Laboratory Standardization. Collection, Transport, and Processing of Blood Specimens for Coagulation Testing and General Performance of Coagulation Assays; Approved Guideline. 5th ed. Villanova, Pa: NCCLS; 2008. Document H21-A5:28(5).

4. Gottfried EL, Adachi MM. Prothrombin time and activated partial thromboplastin time can be performed on the first tube. Am J Clin Pathol. 1997; 107(6):681-683. PubMed 9169665

5. McGlasson DL, More L, Best HA, et al. Drawing specimens for coagulation testing: Is a second tube necessary? Clin Lab Sci. 1999; 12(3):137-139. PubMed 10539100

6. Brandt JT, Triplett DA, Alving B, Scharrer I. Criteria for the diagnosis of lupus anticoagulants: an update. On behalf of the Subcommittee on Lupus Anticoagulant/Antiphospholipid Antibody of the Scientific and Standardisation Committee of the ISTH. Thromb Haemost. 1995 Oct; 74(4):1185-1190. PubMed 8560433

7. Alving BM. The antiphospholipid syndrome: Clinical presentation, diagnosis and patient Management. In: Kitchens CS, Alving BM, Kessler CM, eds. Philadelphia, Pa: WB Saunders Co; 2002: 181-196.

8. Levine JS, Branch DW, Rauch J. The antiphospholipid syndrome. N Engl J Med. 2002; 346(10):752-763. PubMed 11882732

Collection Details:

Patient Preparation:

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.

Collection Instructions:

Blue-top (sodium citrate) tube.

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.

Freeze.