Interference by the catecholic cephalosporin BRL-41897-A with diagnostic clinical chemistry assays

The catecholic cephalosporin BRL-41897-A, was investigated for iii vitro in terference with commonly used clinical chemistry assays. An important findi ng was a negative interference with the enzymatic cholesterol assay that in corporates the Trinder reaction, in which hydrogen peroxide produced by an oxidase drives the oxidative coupling of a phenol with 4-aminophenazone to produce a colored quinoneimine. The suspected interference by BRL-41897-A w ith the Trinder reaction was investigated using a uricase driven system in which the phenol reagent was substituted or combined with BRL-41897-A. The results indicate that BRL-41897-A competes with the phenol component to rea ct preferentially with 4-aminophenazone to produce a quinoneimine of low ab sorptivity. Further investigations conducted with similar enzymatic assays for creatinine, cholesterol, triglycerides, and uric acid showed the interf erence varied substantially with analyte and was dependent on analyte conce ntration.