Quality control measures in the assay of common urinary steroids as applied to a multi-column chromatographic procedure.

Quality control measures in the assay of common urinary steroids include stringent controls not only with details of the procedure but also, through a steady monitoring of the output, with the use of "blind" duplicates, the application of estimates of duplicate variability, comparison of the sum of individual steroids chromatographically estimated with independent total group assays and the use of internal standards in the procedure.