[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.

Fluorometric method for phenylalanine microplate assay adapted for phenylketonuria screening.

We adapted the method of McCaman and Robins for fluorometry of phenylalanine to a microplate assay for routine phenylketonuria screening. Sensitivity is 15 mumol/L for the plasma assay and 30 mumol/L for the dried blood-spot assay, with CV less than 10% for both assays. Results for human plasma by microplate assay correlated well (r = 0.