Interference of peptide binding antibiotics in urinary steroid hormone assay

Abstract

Interference of peptide binding antibiotics in urinary 17-hydroxycorticosteroids (17-OHCS) assay is described. In the urine of subjects given an oral dose of cephalexin and kefglycine, elevated optical density (O. D) has been observed. These drugs, followed by the procedure of 17-OHCS assay show a maximum absorption at 380-390nm with porter-silber reagent both color and blank.
The result by means of thin-layer chromatography showed that the metabolites of these drugs cause the interference in determination and these drugs themselves make little interference.
These drugs, as a result, show an error even with subtraction of blank reagent O. D and since these drugs ofen show an elevated O. D over 1.000, it is impossible to correct the value in practice except to quit the administration of these drugs before the test.