Lupus Anticoagulant Comprehensive w/ Reflex*

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Turnaround Time: 2 - 3 days
CPT Code:

85613; 85670; 85705; 85732

Test Type: 3 mL Plasma, frozen

Overview:

Qualitative detection of lupus anticoagulants in plasma.6

Lupus anticoagulants are antibodies that inhibit one or more of the in vitro phospholipid-dependent tests of coagulation.6-10 Recently, the SCC Subcommittee for the Standardization of Lupus Anticoagulants provided guidelines for the laboratory diagnosis of LA.6 No single screening test can detect all LA-positive patients. The ISTH recommends that any sample suspected of having LA be tested using two or more LA screening tests.6,7 The screening tests commonly used to detect LA assess inhibitors of the intrinsic pathway (aPTT) and the common pathways (dRVVT). The dPT assay screens for phospholipid-dependent inhibitors of a different part of the coagulation cascade, the extrinsic pathway.11 The thrombin time is included to rule out heparin and other thrombin inhibitors.

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 Jan; 107(1):105-110. PubMed 8980376

2. Reneke J, Etzell J, Leslie S, Ng VL, Gottfried EL. 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 Jun; 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; 2008. NCCLS 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 Jun; 107(6):681-683. PubMed 9169665

5. McGlasson DL, More L, Best HA, Norris WL, Doe RH, Ray H. Drawing specimens for coagulation testing: Is a second tube necessary? Clin Lab Sci. 1999 May-Jun; 12(3):137-139. PubMed 10539100

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

7. Brandt JT, Barna LK, Triplett DA. Laboratory identification of lupus anticoagulants: Results of the Second International Workshop for Identification of Lupus Anticoagulants. On behalf of the Subcommittee on Lupus Anticoagulant/Antiphospholipid Antibodies of the ISTH. Thromb Haemost. 1995 Dec; 74(6):1597-1603. PubMed 8772243

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

9. Levine JS, Branch DW, Rauch J. The aAntiphospholipid syndrome. N Engl J Med. 2002 Mar 7; 346(10):752-763. PubMed 11882732

10. Greaves M, Cohen H, MacHin SJ, Mackie I. Guidelines on the investigation and management of the antiphospholipid syndrome. Br J Haematol. 2000 Jun; 109(4):704-715. PubMed 10929019

11. Arnout J, Vanrusselt M, Huybrechts E, Vermylen J. Optimization of the dilute prothrombin time for the detection of the lupus anticoagulant by use of a recombinant tissue thromboplastin. Br J Haematol. 1994 May; 87(1):94-99. PubMed 7947261

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:

This test will reflex immediately to aPTT Mixing Studies [117199] if aPTT is five or more seconds above the upper end of the reference interval.

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.

Freeze.