An evaluation of the TREC assay with regard to the integration of SCID screening into the Dutch newborn screening program

Newborn screening of severe combined immunodeficiency through the detection of T-cell receptor excision circles will provide the opportunity of treating before the occurrence of life-threatening infections. With the EnLite Neonatal TREC assay (PerkinElmer) and end-point PCR, 39 samples (3.0%) of 1295 heel prick cards of the Dutch newborn screening program required a retest after initial analysis. After retest, 21 samples (1.62%) gave TREC levels below cut-off. A significant reduction in TREC levels was observed in heel prick cards stored for three months (n = 33) and one year (n = 33). Preterm newborns (n = 155) showed significantly lower TREC levels and a higher retest-rate than full-term newborns. Peripheral blood spots of 22 confirmed SCID patients and 17 primary immunodeficiency patients showed undetectable or low TREC-levels. These findings suggest that the EnLite Neonatal TREC assay is a suitable method for SCID-screening in the Netherlands, thereby providing guidance in the decisions concerning implementation into the Dutch program.