In the past, various techniques have been employed in industry and medical practice using the occurrence of porphyrins in human urine as a reliable measure of lead intoxication. A literature survey indicates essentially two approaches to the problem have been tried in the past: (1) a visual qualitative test based on the fluorescence of porphyrin in ultra-violet light; (2) a quantitative test based on the separation and isolation of porphyrins using chromatographic methods. These past accepted methods are inconclusive because of inadequacies in the qualitative and quantitative procedures and because high porphyrin concentrations can occur due to other pathological conditions than lead intoxication, e.g., hepatitis and acute alcoholism.The writer proposes to re-examine both the qualitative and quantitative procedures mentioned above in an effort to improve them. Also, by separating the porphyrins found in urine, converting them to their esters, and further isolating the lead-bearing ester by spectroscopy, this writer will attempt to identify the ester containing the ingested lead. the identification of this compound in subsequent cases would warn of early lead exposure, thus giving the physician a reliable tool in eliminating the risk of acute lead intoxication.