Rapid and accurate random urinary porphyrin quantitation.

Urinary metabolite profiling, using randomly voided samples, has become accepted practice for such compounds as organic acids. To date, however, published methods for examining urinary porphyrin excretion have been based upon examination of 24-h urine collections. The inherent difficulties of obtaining an accurate collection, coupled with the intrinsic liabilities of porphyrins suggest that a method based upon random void analysis would be of great use. Thus, we have examined the porphyrin pattern of randomly excreted urine samples from normal adults of both genders, comparing our results with those obtained from analysis of 24-h collections. We have also evaluated the use of different alkalinizing agents. Finally, we have investigated the possibility that an underlying diurnal pattern of porphyrin excretion might influence the results obtained from random urine voids. The results indicate that NaOH retards spontaneous conversion of porphyrins within the first 24 h, thus optimizing recovery of uroporphyrin. Data from random voids mirror those obtained from 24-h collections and diurnal variations were not found to influence these results. Normal values are provided for random samples obtained from males and females. Thus, we conclude that random urine profiling is a rapid and accurate means of initial evaluation.