INTERFERENCE IN CLINICAL LABORATORY TESTS, WITH SPECIAL REGARD TO THEBILIRUBIN ASSAY - EFFECTS OF A METABOLITE OF THE NEW PROLYL 4-HYDROXYLASE INHIBITOR, LUFIRONIL

During the toxicological examination of the fibrosuppressive agent, Lu fironil (INN), in rats a dose-dependent positive reaction for urinary bilirubin was observed. This positive reaction was found in quantitati ve assays, and when using test strips. The positive reaction for bilir ubin in these assay systems was caused by a metabolite of Lufironil. I t was not due to drug toxicity, and it was not caused by any endogenou s substrate produced under the influence of Lufironil. The compound re sponsible for this reaction was isolated by HPLC and its structure det ermined by spectroscopic methods. The structure was confirmed by synth esis, starting from pyridine-2,4-dicarboxylate. The synthesized compou nd and the compound in urine gave an identical reaction with the test reagent for bilirubin.