A one-and-a-half year experience with expanded newborn screening (ENBS) in Slovakia provided by means of tandem mass spectrometry (LC-MS/MS) is presented.
Method ENBS was realised from dry blood samples of the regular NBS in National Screening Centre SK. The LC-MS/MS software used allowed evaluating even 73 analytes in MRM mode after cut-of limits in 99 percentile of daily values. The regular ENBS was oriented to 10 inherited metabolic disorders (IMDs), organic acids and carnitine defects (PKU/HPA, MSUD, GAI, IVA, MCAD, LCHAD, SCAD, CPT I, CPT II, CACT). Except these, many other variations of results were registered in perimeter of the method. They were individually evaluated until the confrmation or exclusion of the suspected diagnosis.
Results During the one-and-a-half years, 82 892 newborns were evaluated by ENBS and 34 positive cases of IMDs were detected and confrmed, which represents a screening prevalence of 1:2438 newborns. Out of these, 24 cases were from regular ENBS (PKU/HPA, MSUD, MCAD) with an incidence of 1:3 454, and 10 additional cases at the periphery of LC-MS/MS evaluation with a prevalence of 1:8 286.
Conclusion Preliminary experience and results with ENBS confrmed its high efectiveness not only in 10 IMDs included in regular ENBS, but also at perimeter of LC-MS/MS method, in which it is possible to detect additional IMDs not included in regular spectrum of ENBS. This group comprised 29% of all cases. In general, the prevalence is comparable with PKU and/or CAH.
