A CLIMATOLOGICAL FACTOR INFLUENCING DETERMINATION OF PHENYLALANINE IN BLOOD OF NEWBORN INFANTS IN NORTH CAROLINA

Data obtained from screening newborn babies for elevated blood phenylalanine levels by the widely used technique of using punched discs from blood-soaked filter paper coupled with an automated fluorometric procedure revealed a seasonal variation in apparent" blood phenylalanine concentrations. The variation was shown to be related to variations in relative humidity. The more humid the surrounding atmosphere the more the blood spreads through the filter paper and the less will be contained in a punched disc. The need in certain instances for a more precise means of quantification is discussed. © 1969."