Search

The analysis of urine in order to identify errors of amino acid metabolism is now a widely employed procedure. Currently the most popular methods utilize urine samples and the technic of paper chromatography, with various modifications of the unidimensional and bidimensional systems originally described by Consden and associates. A handicap in these methods, however, is the frequent difficulty in obtaining urine specimens from neonates or young infants. This problem is especially acute when large numbers of these infants are tested in a screening program. To obviate this, the urine screening program for metabolic disorders currently being conducted in Massachusetts, by the Massachusetts Department of Public Health in a cooperative project with the Massachusetts General Hospital, utilizes a method of urine collection that involves placing a 5by 2.5-cm. strip of Whatman No. 3MM filter paper* inside the diaper. The urine-impregnated strip is then analyzed by unidimensional paper chromatography according to the technic of Efron and colleagues. Since the inception of the urine screening program, an occasional specimen has revealed an increased quantity of many of the amino acids normally present in urine, as well as an increased quantity of the imino acid, proline, but not of hydroxyproline. Repeat specimens from infants with this amino and imino acid pattern have invariably yielded normal chromatograms, and inspection of the original filter papers has