SPOT-it™ TREC & KREC Screening Kit is an in vitro diagnostic (IVD) kit intended for newborn screening for severe combined immunodeficiency (SCID) and agammaglobulinemia (XLA). The kit quantifies T-cell receptor excision circle (TREC) DNA and kappa-deleting recombination excision circles (KREC) DNA extracted from fresh, prospective dried blood spot (DBS) sampled on filter paper. The analysis is performed by semi-quantitative real-time polymerase chain reaction (qPCR).

The test is intended for use by laboratory professionals to aid in identifying newborns who potentially suffer from SCID caused by lack of mature T- or T and B-cells or XLA caused by lack of mature B-cells.

TRECs and KRECs are produced during the maturation of T-cells and B-cells respectively — vital components of the immune system. Lack of TRECs and KRECs indicate low or no production of mature T- and B-cells. A newborn identified with low TRECs or with low TRECs and KRECs can potentially suffer from SCID, while a newborn identified with low KRECs can potentially suffer from XLA. Confirmatory testing should be performed before diagnosis.