Inter-laboratory quality control in neonatal screening for inborn errors of metabolism

Screening of neonates for inborn errors of metabolism has been carried out on a national level since 1969 in the Federal Republic of Germany. To raise the reliability of these routine investigations, we introduced an external quality control in March 1982. Every 2 months ten filter paper samples were sent to the screening centres in West Germany. Some of these samples have a normal and others a slightly raised content of phenylalanine, leucine, methionine and galactose. The success of this external quality control is appraised on the basis of the number of false negative results. In the course of time, screening centres in France, Israel, Italy, Japan, Switzerland, Taiwan, Turkey and Yugoslavia have also participated in these inter-laboratory quality controls.