[Methods of determining phenylalanine in blood and blood stains dried on paper]

Two modifications of the method developed by McCaman and Robins are suggested for the screening of newborns for phenylketonuria and for monitoring the treatment of the detected patients. Phenylalanine levels are measured in the plasma and blood stains dried on the paper for express tests, brand 2, with the use of high-capacity (96 analyses per minute) Fluoroscan-2 fluorometer (Labsystems OY, Finland). A high analytical reliability of the methods is demonstrated. Use of microplates permits taking the minimal volumes of the tested material and reagents.