[The function and the significance of full-automated tests for detecting antiphospholipid antibodies]

Antiphospholipid antibodies (aPLs) are a group of heterogenous antibodies with immunological and functional variations that are detected in the sera of patients with antiphospholipid syndrome (APS). Detection of these antibodies in an efficient and accurate manner remains a significant issue. It requires numerous immunological and functional tests, burdening the laboratory departments, and as a consequence, not sufficiently performed in many cases. We retrospectively studied a total of 212 subjects with or without collagen diseases including APS that visited the outpatients of multiple institutions (department of internal medicine at Health Science University of Hokkaido, department of medicine II and department of gastroenterology at Hokkaido University Hospital). All the subjects were measured aPL (anticardio anticardiolipin antibody IgG/IgM, anti-β2-glycoprotein I antibody IgG/IgM) using a fully automated chemiluminescence analyzer and compared measurement results with those obtained using the conventional ELISA method. These methods were found to have similar diagnostic accuracy, with κ values exceeding 0.6. Of 61 APS patients 41 (67%) were positive for two or more tests: significantly higher than other disease such as systemic lupus erythematosus (3/37, 9%) or non-SLE collagen disease (1/53, 2%). The fully automated chemiluminescence analyzer, which can simultaneously measure multiple aPLs, was thus determined to be useful for diagnosing APS.