20.500.12556/RUL-155551 Comparison of tandem mass spectrometry and the fluorometric method parallel phenylalanine measurement on a large fresh sample series and implications for newborn screening for phenylketonuria Phenylketonuria (PKU) was the first disease to be identified by the newborn screening (NBS) program. Currently, there are various methods for determining phenylalanine (Phe) values, with tandem mass spectrometry (MS/MS) being the most widely used method worldwide. We aimed to compare the MS/MS method with the fluorometric method (FM) for measuring Phe in the dried blood spot (DBS) and the efficacy of both methods in the NBS program. The FM was performed using a neonatal phenylalanine kit and a VICTOR2$^{TM}$ D fluorometer. The MS/MS method was performed using a NeoBase$^{TM}$ 2 kit and a Waters Xevo TQD mass spectrometer. The Phe values measured with the MS/MS method were compared to those determined by the FM. The cut-off value for the NBS program was set at 120 µmol/L for FM and 85 µmol/L for MS/MS. We analyzed 54,934 DBS. The measured Phe values varied from 12 to 664 µmol/L, with a median of 46 µmol/L for the MS/MS method and from 10 to 710 µmol/L, with a median of 70 µmol/L for the FM. The Bland–Altman analysis indicated a bias of −38.9% (−23.61 µmol/L) with an SD of 21.3% (13.89 µmol/L) when comparing the MS/MS method to the FM. The Phe value exceeded the cut-off in 187 samples measured with FM and 112 samples measured with MS/MS. The FM had 181 false positives, while the MS/MS method had 106 false positives. Our study showed that the MS/MS method gives lower results compared to the FM. Despite that, none of the true positives would be missed, and the number of false-positive results would be significantly lower compared to the FM. tandem mass spectrometry MS/MS fluorometric method FM comparison phenylalanine Phe phenylketonuria PKU newborn screening NBS false positive results recall rate tandemska masna spektrometrija MS/MS fluorometrična metoda FM primerjava fenilalanin Phe fenilketonurija pregled novorojenčka PKU lažno pozitivni rezultati NBS stopnja odpoklica true false true Angleški jezik Slovenski jezik Članek v reviji 2024-04-05 13:49:28 2024-04-05 13:49:31 2024-04-06 04:17:39 0000-00-00 00:00:00 2023 0 0 11 str. iss. 3, art. 2487 Vol. 24 2023 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 616-053.2 1422-0067 10.3390/ijms24032487 147446787 ijms-24-02487-v2.pdf ijms-24-02487-v2.pdf 1 C1E659ED8BF9FFCCB6ED8F1E0EE6504E eb6bbb4928fee6ddf9f0c646c2a44f1ba2409f9de203399e62fd5142fce41ca6 0e1c648b-f343-11ee-afc9-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=182511 https://www.mdpi.com/1422-0067/24/3/2487 0 907b20f5-f342-11ee-afc9-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=182510 Medicinska fakulteta 0 0 0