Letters to the Editor
12 to 20 mg. per cent. The urines taken at 2 to 3 weeks of age have been somewhat more troublesome and definitely less satisfactory than the specimens of blood. On the definitely positive side, out of the 50,000 specimens tested by the Guthrie technique, 8 have displayed readings above 20 mg. per cent. Each of these 8 positive results has been confirmed both by repeat Guthrie tests and by independent hospital serum phenylalanine determinations as recounted in the appendix of case summaries enclosed. The great value in detecting these 8 cases seems to us a very ample reward for the work involved. They are quite beyond the number we expected to find in the specimens done so far, and together with the case detected in the first five other newborn PKU cases detected in other parts of the country, they suggest that phenylketonuria may be more frequent than the 1 in 20,000 estimate usually quoted. In any case we are looking forward with great interest to the results of the screening programs planned in other states, and hopefully in other countries as well.
ROBERT A. MAC CREADY~ M.D. DIRECTOR, DIAGNOSTIC LABORATORIES COMMONWEALTtI
Editor's note Dr. MacCready's letter included an appendix with summaries of the three patients discovered in Massachusetts by use of the Guthrie assay method. In each instance, the diagnosis was confirmed by direct clinical determinations. W.E.N.
II. Poole To the Editor: In view of the importance of early detection of phenylketonuria in young infants, the simplicity of the diaper test, and the negligible or extremely low cost of this procedure, it seems urgent that some of: the statements and observations made by Dr. Stanley Wright, in the editorial of the October issue of The JOURNAL OF PEDIATRICS, be immediately challenged by facts collected from actual operational experience. At the present time in CalifOrnia, phenylketonuria diaper testing is a routine ,procedure in almost all of the local health departments, affect-
ing over 80 per cent of all infants and children attending the Child Health Conferences. In 1960 there were 604 Child Health Conference Centers serving 98,333 infants and 72,143 preschool children; 19 per cent of the new live births (372,210) in the State in that calendar year were registered in Child Health Conferences. The following data were obtained very recently from the Los Angeles City Health Department: 1. Phenylketonuria diaper testing in the Child Health Conference was started in 1957. From that date through September, 1962, over 65,000 infants under 1 year of age have been admitted tO the Child Health Conference Service. An average of 3 phenylketonuria diaper tests per infant have been performed. 2, During this period 2 infants with positive phenylketonuria tests have been identified, 1 in 1957, aged 11 months, and another in 1962, aged 4 months. For the same period 4 false-positive tests have occurred. As far as is known, there have been no false-negative tests. 3. The cost for this service, which, I must remind you, included 2 identified cases of phenylketonuria, has been negligible. The test material is obtained without cost from the White Memor[al Hospital in Los Angeles. Dr. Lillian Kositza, Director of Maternal and Child Health Division of the Los Angeles City Health Department, says: "The test itself is such a simple procedure that it is just absorbed in nursing services at the Child Health Conference. The same applies to cIerical services involved." In a short time we hope to report on the total Child Health Conference experience in the California phenylketonuria diaper testing program. From our experience during a 5 year period, we consider this test valuable, simple, and relatively inexpensive.
C H I L D HEALTH
B U R E A U OF M A T E R N A L A N D CH I L D H E A L T H CALIFORNIA ST A T E D E P A R T M E N T OF p U B L I C H E A L T H
III. Brandon and Ashley To the Editor: In a recent publication (J. PEDIAT. 62: 610, 1962) Scheel and Berry have reported their