Thromb Haemost 1992; 67(06): 672-678
DOI: 10.1055/s-0038-1648521
Original Articles
Schattauer GmbH Stuttgart

Comparison Between a One-Point Dilute Phospholipid APTT and the Dilute Russell Viper Venom Time for Verification of Lupus Anticoagulants

Barbara M Alving
The Department of Hematology and the Division of Biometrics, Walter Reed Army Institute of Research, Washington, DC, USA
,
Charles F Barr
The Department of Hematology and the Division of Biometrics, Walter Reed Army Institute of Research, Washington, DC, USA
,
Lawrence E Johansen
The Department of Hematology and the Division of Biometrics, Walter Reed Army Institute of Research, Washington, DC, USA
,
Douglas B Tang
The Department of Hematology and the Division of Biometrics, Walter Reed Army Institute of Research, Washington, DC, USA
› Author Affiliations
Further Information

Publication History

Received 07 November 1991

Accepted after revision 24 January 1992

Publication Date:
03 July 2018 (online)

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Summary

In the present study, the dilute Russell viper venom time (RVVT) and the dilute phospholipid activated partial thromboplastin time (PL-APTT), which are two assays used for the verification of lupus anticoagulants (LA), were modified to increase standardization. The modified assays were then compared with respect to sensitivity and specificity in detecting LA in plasmas from 72 patients with a prolonged APTT. Modifications included utilizing a single dilution of phospholipid that was either bovine brain thromboplastin (Thrombofax) or liposomes comprised of phosphatidylcholine/phosphatidylserine, and expressing the results as a ratio of the clotting times of the mixture of patient and normal plasma/clotting time of normal plasma. In the RWT, the correlation coefficient between assay results for liposomes and Thrombofax was 0.88 and in the PL-APTT, the correlation was 0.68. A positive test for LA was defined as a ratio of ≥1.3 for the PL-APTT with liposomes and ≥1.2 for the PL-APTT with Thrombofax and the RWT with Thrombofax or liposomes. Regardless of the phospholipid source in the test system, the PL-APTT demonstrated higher sensitivity and the RWT showed greater specificity in detecting patient plasmas that contained antiphospholipid antibodies.