Mass screening for glucose-6-phosphate dehydrogenase deficiency: improved fluorescent spot test.

New data on the reliability of the fluorescent spot test are presented. Improvements in the assay were established. Newborn mass screening for glucose-6-phosphate dehydrogenase (G-6-PD, EC 1.1.1.49) deficiency was performed with dried blood samples on filter paper (Guthrie-cards). Females, known to be heterozygote for G-6-PD deficiency were detected at a rate of approximately 30-70%, depending on the storage conditions of the samples. False positive results in male hemizygotes were eliminated.