Detection and quantification of lupus anticoagulants in plasma from heparin treated patients, using addition of polybren
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BioMed Central
Open Access
Original basic research
Detection and quantification of lupus anticoagulants in plasma from heparin treated patients, using addition of polybrene Eva M Jacobsen*1, Elin J Trettenes2, Finn Wisløff1 and Ulrich Abildgaard2 Address: 1Haematological Research Laboratory, Ullevål University Hospital, Kirkeveien 166, N-0407 Oslo, Norway and 2Haematological Research Laboratory, Aker University Hospital, N-0514 Oslo, Norway Email: Eva M Jacobsen* - [email protected]; Elin J Trettenes - [email protected]; Finn Wisløff - [email protected]; Ulrich Abildgaard - [email protected] * Corresponding author
Published: 25 January 2006 Thrombosis Journal 2006, 4:3
doi:10.1186/1477-9560-4-3
Received: 18 October 2005 Accepted: 25 January 2006
This article is available from: http://www.thrombosisjournal.com/content/4/1/3 © 2006 Jacobsen et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract Background: Lupus anticoagulants prolong clotting times in phospholipid-dependent coagulation tests. Lupus Ratio assays are integrated tests for lupus anticoagulants that may be based on APTT, RVVT or dPT clotting times. If a patient is being treated with unfractionated heparin, however, the heparin prolong clotting times and the diagnosis of lupus anticoagulant is invalidated. Commercial assays may have heparin neutralising agents added to their reagents. However, the type and efficacy of the heparin neutralisation is often not documented. We wanted to test the influence and efficacy of heparin neutralisers in the Lupus Ratio assay. Methods: Several heparin neutralisers were tested, and polybrene was chosen for further testing. Unfractionated heparin and/or polybrene were added to normal plasma and to plasma from patients with or without lupus anticoagulant and clotting times compared before and after the additions. Lupus anticoagulant-positive patients were given 5000 IU i.v. of unfractionated heparin and plasma was collected just before and five minutes after the injection. Lupus Ratios were calculated after polybrene was added to the postinjection samples. Results: The Lupus Ratio became slightly lower when polybrene was added to plasma without heparin. Plasma heparinised in vitro and plasma from patients that had received heparin, both had Lupus Ratios nearly identical to the Lupus Ratios calculated before any additions. Conclusion: By addition of polybrene to a final concentration of 7.9 µg/ml in test plasma, Lupus Ratio may be determined in lupus anticoagulant-negative as well as positive plasmas irrespective of the presence of heparin 0.0 – 1.3 U/ml.
Background Lupus anticoagulants (LAs) are a heterogeneous group of antibodies directed against phospholipidbinding (PLbinding) proteins or complexes of PLs and proteins [1].
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