Objective: To confirm preparedness of our department for newborn screening of 19 inherited metabolic disorders (IMDs) by tandem mass spectrometry (MS/MS). Material and Method: We analysed 40 393 samples from newborn screening and 13 315 samples from patients suspected for IMDs. Control group was 1130 samples from 118 patients with confirmed IMDs. Results: Sensitivity of the method in control group was 97.5%. In newborn screening, we detected 7 patients with IMDs: 4 with phenylketonuria/hyperphenylalaninemia (PKU/HPA), two with disorders of fatty acids β-oxidation and one with methylmalonic acidemia (MMA). The overall incidence of IMDs in newborn population was 1 : 5771. In the prospective selective screening, we diagnosed IMDs in 14 patients: 9 with disorders of fatty acids β-oxidation, three with PKU/HPA, one with tyrosinemia type I and one with MMA. Conclusion: Early diagnostics of treatable IMDs before clinical symptoms together with genetic counselling and prenatal diagnostics represent the most effective medical approach to IMDs. We are now able to diagnose 19 IMDs in newborn screening by MS/MS.

        Key words: inborn errors of metabolism, newborn screening, tandem mass spectrometry.