A Rapid and Reliable Kinetic Immunonephelometric Method (I.N.) for Routine Assay of Total IgA in Human Bile

Abstract

Usual methods have been shown to underestimate high molecular weight Igs and particularly IgA; sophisticated techniques are time-consuming and more suitable for research studies. We developed a I.N. method using the “manual mode” (I.C.S., Beckman) to measure IgA, directly in human bile. The manual-mode-calibration-card M 33 was shown to be suitable for this purpose and to offer the better sensitivity. Working range and measuring range were determined. Mean and extreme values of total IgA obtained in 20 samples of human bile with this technique were 141 mg/1 (20-350). Individual values obtained with this method correlated well with those obtained in the same samples with an immuno-radiometric assay. The coefficient of variation did not exceed 5%. The sensitivity of the manual mode I.N. averaged 10 mg/1 and, as I.N. is not influenced by size heterogeneity in Igs, I.N. appears to be a rapid (60 sec.) and reliable method for routine evaluation of total IgA in bile.