[Evaluation of sensitivity and specificity of confirmatory assays for lupus anticoagulant (LA) detection].
To evaluate the sensitivity and specificity of confirmatory assays for LA detection, we performed the platelet neutralization procedure (PNP), diluted Russell's viper venom time (dRVVT) confirmatory assay (the ratio of LA-screen and LA-confirm:S/C), and specific hexagonal phase neutralization test (StaLA) on, plasma samples 43 LA-positive in either the ratio of dilute APTT and APTT(dAPTT/APTT) or dRVVT(LA-screen). The sensitivity and the specificity were evaluated by 4 different analyses based on, 1) maximal plasma dilution, 2) correlation between the screening assays and these confirmatory assays, 3) ratio of LA-positive in the confirmatory assays, and 4) receiver operation characteristic (ROC) method. All 4 analyses showed that sensitivity was in the order of PNP > S/C > Staclot-LA. However, the order of the specificity evaluated by the ROC method was Staclot-LA > S/C > PNP. The APTT-based confirmatory assay, PNP can detect LA of the plasma samples that were all positive in the dAPTT/APTT ratio, while the LA-positive plasma samples in dRVVT-confirm were all positive in the dRVVT-screen assay. Our findings suggest that confirmatory assays should be based on the method giving an abnormal screening assay. Accordingly, we recommend the following combinations of screening and confirmatory assays in terms of specificity; 1) dAPTT/APTT ratio and Staclot-LA as the APTT-based assay, and 2) LA-screen and LA-confirm as the dRVVT-based assay.
Imoto
K
K
Clinical Laboratory, St. Marianna University, School of Medicine, Kawasaki.
Yasumuro
Y
Y
Taki
M
M
Suzuki
Y
Y
Akatu
S
S
Tajima
C
C
Ichikawa
Y
Y
D001780:Blood Coagulation Tests / Q000379:methods*; D001792:Blood Platelets / Q000276:immunology*; D006801:Humans; D007201:Indicator Dilution Techniques; D007223:Infant; D016682:Lupus Coagulation Inhibitor / Q000097:blood*; D009500:Neutralization Tests / Q000379:methods*; D010314:Partial Thromboplastin Time; D012372:ROC Curve; D011933:Reagent Kits, Diagnostic; D012680:Sensitivity and Specificity
D016682:Lupus Coagulation Inhibitor; D011933:Reagent Kits, Diagnostic