Mass spectrometry in clinical chemistry: the case of newborn screening

tNewborn screening (NBS) program is a complex and organized system consisting of family and personneleducation, biochemical tests, confirmatory biochemical and genetic tests, diagnosis, therapy, and patientfollow up. The program identifies treatable metabolic disorders possibly when asymptomatic by usingdried blood spot (DBS). During the last 20 years tandem mass spectrometry (TMS) has become the leadingtechnology in NBS programs demonstrating to be versatile, sensitive and specific. There is consistent evi-dence of benefits from NBS for many disorders detected by TMS as well as for congenital hypothyroidism,cystic fibrosis, congenital adrenal hyperplasia by immune-enzymatic methods.Real time PCR tests have more recently been proposed for the detection of some severe combinedimmunodeficiences (SCID) along with the use of TMS for ADA and PNP SCID; a first evaluation of theircost-benefit ratio is still ongoing. Avoiding false negative results by using specific biomarkers and reducingthe false positive rate by using second tier tests, is fundamental for a successful NBS program. The fullyintegration of NBS and diagnostic laboratories with clinical service is crucial to have the best effectivenessin a comprehensive NBS system.