The association of serum antiphospholipid antibodies and dilute Russell's viper venom times. Issue 5 (10th December 2013)

• Record Type: Journal Article
• Authors: Froom, Paul; Saffuri-Elias, Enas; Rozenberg, Orit; Barak, Mira
• Is Part Of: Journal of clinical pathology. Volume 67:Issue 5(2014)
• Page Start: 441
• Page End: 444
• Publication Date: 2013-12-10
• Subjects: ANTIBODIES -- ANTIPHOSPHOLIPID -- HAEMATOLOGY -- HAEMOPHILIA -- LABORATORY TESTS; Pathology -- Periodicals; Pathology, Molecular -- Periodicals; 616.0705
• DOI: 10.1136/jclinpath-2013-201830
• Languages: English
• ISSNs: 0021-9746

Abstract

Abstract : Aims: We hypothesised that there is a threshold value for the association of dilute Russell's viper venom times (dRVVT) with positive immunoglobin G antiphospholipid antibody (IgG-APLA) test results. Methods: We tested 120 controls and a cohort of 2412 outpatients who had concomitant test results for dRVVT and IgG-APLA (IgG antibodies to cardiolipins and β2 -glycoprotein I). We also selected a subgroup who had repeated IgG-APLA tests at least 12 weeks apart (1398 patients with multiple β2 -glycoprotein I tests and 672 with multiple aCL tests). We cross tabulated the proportion of IgG-APLA single positive, double positive and persistently positive antibodies with dRVVT values. Results: The distribution of the dRVVT results from the reference population was consistent with an upper limit of the reference interval of 1.22 to >1.48. A consistent increase in the proportion of IgG-APLA single, double positive and persistently positive antibody tests occurred in the group with a normalised dRVVT ratio of 1.40–1.49. IgG-APLA double positivity was found in 12.5% (4 of 32) patients with a ratio of dRVVT 1.40–1.49 compared with 3.3% (6/181) of those with a ratio of dRVVT 1.20–1.39 (p=0.045). Conclusions: We conclude that there is an association between dRVVT positivity and elevated proportions of single, double and persistently positive IgG-APLA test results with an apparent threshold effect. These findings may provide a general guide to risk and suggest a way to choose from a wide range of possible upper limits of the reference interval.