Tandem Mass Spectrometry in Newborn Screening: CLSI Solves the Puzzle

In the mid-1990's, tandem mass spectrometry (MS/MS), the most versatile and possibly most significant advancement in newborn screening (NBS) technology was put into practice in private and academic laboratories. Today, the use of MS/MS has spread to almost all newborn screening programs worldwide. While the number of disorders detectable by MS/MS has been debated due to variations in the number of metabolites measured, the interpretation of data and even public policy, the total figure is still impressive. In an official statement in 2004, the American College of Medical Genetics suggested that 35 of the 54 disorders currently available for testing are detected through MS/MS. The inherent versatility of tandem mass spectrometry allows it to be adapted to the user's testing preferences, thereby creating numerous variations in NBS analysis and determinations. Differences in specimen and reagent preparation, calibration, validation, result-reporting, and interpretation have led to difficulties when comparing results between laboratories. Here, guidelines for newborn screening laboratories called CLSI I/LA32-A, Newborn Screening by Tandem Mass Spectrometry is discussed.