Use of micromethod for phenylalanine in management of phenylketonuric patients.

FREATMENT of phenylketonuric infants with low phenylalanine diet requires frequent measurements of blood phenylalanine, since diet must be adjusted to changing phenylalanine requirements. The amount of blood required for repetitive determinations by the usual methods may be excessive. The need for frequent and rapid determinations led us to modify the method for serum phenylalanine (1) to permit use of blood obtained from a finger puncture-a modification suggested by methods for microchemical analysis for other blood constituents (2).