Comparative analysis of different enzyme immunoassays for assessment of phosphatidylserine-dependent antiprothrombin antibodies.
Phosphatidylserine-dependent antiprothrombin antibodies (aPS/PT) were strongly correlated with the presence of lupus anticoagulant showing a high specificity for the diagnosis of antiphospholipid syndrome. However, the main criticism for the clinical applicability of aPS/PT testing is the lack of reproducibility of the results among laboratories. In this study, we measured IgG and IgM aPS/PT using our original in-house enzyme-linked immunosorbent assays (ELISA) and commercial ELISA kits to assess the assay performance and to evaluate the accuracy of aPS/PT results. The study included 111 plasma samples collected from patients and stored at our laboratory for aPS/PT assessment. Sixty-one samples were tested for IgG aPS/PT using two assays: (1) aPS/PT in-house ELISA and (2) QUANTA Lite™ aPS/PT IgG ELISA kit (INOVA Diagnostics, Inc., USA). Fifty samples were evaluated for IgM aPS/PT using two assays: (1) aPS/PT in-house ELISA and (2) QUANTA Lite™ aPS/PT IgM ELISA kit (INOVA Diagnostics). Ninety-eight percent of samples yielded concordant results for IgG aPS/PT and 82 % for IgM aPS/PT. There was an excellent agreement between the IgG aPS/PT assays (Cohen κ = 0.962) and moderate agreement between the IgM aPS/PT assays (κ = 0.597). Statistically significant correlations in the aPS/PT results were obtained from both IgG and IgM aPS/PT assays (r = 0.749, r = 0.622, p < 0.001, respectively). In conclusion, IgG and IgM detection by ELISA is accurate. The performance of aPS/PT is reliable, and concordant results can be obtained using different ELISA methods.
Division of Rheumatology, Endocrinology and Nephrology, Hokkaido University Graduate School of Medicine, N15 W7, Kita-ku, Sapporo, 060-8638, Japan, olgaam@med.hokudai.ac.jp.
Olga
O
Amengual
Tetsuya
T
Horita
Walter
W
Binder
Gary L
GL
Norman
Zakera
Z
Shums
Masaru
M
Kato
Kotaro
K
Otomo
Yuichiro
Y
Fujieda
Kenji
K
Oku
Toshiyuki
T
Bohgaki
Shinsuke
S
Yasuda
Tatsuya
T
Atsumi
D000328:Adult; D000368:Aged; D017152:Antibodies, Antiphospholipid / Q000097:blood*; D016736:Antiphospholipid Syndrome / Q000097:blood / Q000175:diagnosis* / Q000276:immunology; D015415:Biomarkers / Q000097:blood; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods* / Q000592:standards; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood*; D007075:Immunoglobulin M / Q000097:blood*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D010718:Phosphatidylserines / Q000276:immunology*; D011237:Predictive Value of Tests; D011516:Prothrombin / Q000276:immunology*; D011786:Quality Control; D011933:Reagent Kits, Diagnostic; D015203:Reproducibility of Results; D055815:Young Adult
D017152:Antibodies, Antiphospholipid; D015415:Biomarkers; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D010718:Phosphatidylserines; D011933:Reagent Kits, Diagnostic; D011516:Prothrombin