Computer assisted validation of binding assays for sex hormone binding globulin

Accurate measurement of sex hormone binding globulin (SHBG) by 5 alpha-dihydrotestosterone (DHT) binding assays requires the establishment of acceptable upper and lower limits of labelled DHT binding and the use of optimal quantities of radioinert DHT to displace labelled DHT. A computer assisted binding assay for SHBG is described in which upper and lower binding limits are derived mathematically from analysis of labelled DHT binding to eight concentrations of SHBG in the range 25 to 400 nM. The optimal quantity of radioinert DHT for a given SHBG concentration is also derived from these binding curves. A computer program determines whether or not, in a given sample, the binding of labelled DHT falls within these established binding limits and also calculates the concentration of SHBG. This technique reduces the number of tubes required in an assay and provides rapid validation and calculation of results.