Coproporphyrin Analyses on Random Urine Samples.

The fluorometric procedure of determining coproporphyrin has been adapted to determine coproporphyrin on random urine specimens. This adaptation depends on determining both coproporphyrin and creatinine. A mathematical relationship is established for the amount of coproporphyrin excreted when 1200 mg. of creatinine is excreted. An important advantage of the random procedure is the elimination of the waiting period of 24 hr. for the urine collection. This is particularly important in porphyric urines since much of the porphyrin is reduced to forms that are sensitive to light, with the result that pathologic levels of coproporphyrin may thus be overlooked.