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An enzyme‐linked immunosorbent assay for the quantification of serum platelet‐bindable IgG
Author(s) -
Howe SE,
Lynch DM,
Lynch JM
Publication year - 1984
Publication title -
transfusion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.045
H-Index - 132
eISSN - 1537-2995
pISSN - 0041-1132
DOI - 10.1046/j.1537-2995.1984.24484275580.x
Subject(s) - platelet , microtiter plate , antibody , predictive value , standard curve , chemistry , immunology , coefficient of variation , medicine , microbiology and biotechnology , enzyme , chromatography , biology , biochemistry
An enzyme‐linked immunosorbent assay (ELISA) using F(ab')2 peroxidase‐ labeled antihuman immunoglobulin and o‐phenylenediamine dihydrochloride (OPD) as a substrate was developed to measure serum platelet bindable IgG (S‐PBIgG). The assay was made quantitative by standardizing the number of normal “target” platelets bound to microtiter plate wells, and by incorporating quantitated IgG standards with each microtiter plate tested to prepare a standard calibration curve. By this method, S‐ PBIgG for normal individuals was 3.4 +/− 1.6 fg per platelet (mean +/− 1 SD; n = 40). Increased S‐PBIgG levels were detected in 36 of 40 patients with clinical autoimmune thrombocytopenia (ATP), ranging from 7.0 to 85 fg per platelet. Normal S‐PBIgG levels were found in 34 of 40 patients with nonimmune thrombocytopenia. This method showed a sensitivity of 90 percent, specificity of 85 percent, and in the sample population studied, a positive predictive value of 0.86 and a negative predictive value of 0.90. This assay is highly reproducible (coefficient of variation was 6.8%) and appears useful in the evaluation of patients with suspected immune‐mediated thrombocytopenia.