Usporedba koncentracija fenilalanina, tirozina i njihovih omjera (Phe/Tyr) izmjerenih na dvama tandemskim spektrometrima masa u svrhu novorođenačkog probira i praćenja metaboličke kontrole pacijenata s fenilketonurijom

master's thesis

• Title (english): Comparison of phenylalanine and tyrosine concentrations and their molar ratio (Phe/Tyr) measured on two tandem mass spectrometers for purposes of newborn screening and follow up of patients with phenylketonuria
• Author: Donatella Čagljević
• Mentor: Ksenija Fumić (mentor)
• Committee member: Ksenija Fumić (predsjednik povjerenstva)
• Committee member: Nada Vrkić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Pharmacy and Biochemistry; (Department of medical biochemistry and haematology); Zagreb
• Defense date and country: 2018-06-20, Croatia
• Scientific / art field, discipline and subdiscipline: BIOMEDICINE AND HEALTHCARE; Pharmacy; Medical Biochemistry

Abstract

Novorođenački probir na fenilketonuriju u Republici Hrvatskoj provodi se centralizirano, u Odjelu za laboratorijsku dijagnostiku nasljednih metaboličkih bolesti i novorođenački probir KBC-a Zagreb od 1978. godine. 2017. godine u Hrvatskoj započinje prošireni novorođenački probir tandemskom spektrometrijom masa. Ključni metaboliti u novorođenačkom probiru na fenilketonuriju tandemskom spektrometrijom masa jesu aminokiseline fenilalanin i tirozin, a omjer koncentracija fenilalanina i tirozina dodatno povećava dijagnostičku specifičnost, odnosno smanjuje udio lažno pozitivnih rezultata. Cilj ovog rada bilo je ispitati usporedivost dvaju tandemskih spektrometara masa, UPLC Nexera-API3200, AB Sciex i UPLC Nexera-MS8050, Shimadzu u određivanju koncentracija aminokiselina fenilalanina, tirozina te njihovih koncentracijskih omjera (Phe/Tyr), koristeći uzorke suhe kapi krvi novorođenčadi te PKU pacijenata. Passing Bablok te Bland Altman statističkom analizom utvrđeno je postojanje statistički značajne razlike u rezultatima svih promatranih parametara, tj. vrijednosti dobivene tandemskim spektrometrom masa UPLC Nexera-MS8050 u prosjeku su 6,5%, 2,9% i 3,5% više u odnosu na mjerenja dobivena na UPLC Nexera-API3200, što se može objasniti većom osjetljivošću UPLC Nexera-MS8050. Utvrđena srednja razlika za vrijednosti omjera Phe/Tyr od 0,04 μmol/L ne smatra se i klinički značajnom, tj. unatoč konstantnoj i proporcionalnoj razlici u koncentracijama fenilalanina, zaključujemo kako istovremeno praćenje koncentracija fenilalanina i omjera Phe/Tyr opravdava simultano korištenje ispitivanih tandemskih spektrometara za postavljanje sumnje na fenilketonuriju pri novorođenačkom pobiru.

Abstract (english)

Newborn screening for Phenylketonuria in Republic of Croatia has been centrally organized, in the Department of laboratory diagnostics of inherited metabolic disorders and newborn screening at University Hospital Centre Zagreb, since 1978. Since 2017 Croatia has started expanded NBS with tandem mass spectrometry. Key metabolites included in newborn screening for phenylketonuria by tandem mass spectrometry are aminoacids phenylalanine and tyrosine, and their molar Phe/Tyr ratio further enhances the diagonstic specifity, i.e. reduces the false positive ratio. The aim of this thesis was to examine the differences between two tandem mass spectrometers, UPLC Nexera-API3200, AB Sciex i UPLC Nexera-MS8050, Shimadzu, for phenylalanine and tyrozine concentrations, as well as their molar ratio (Phe/Tyr), in dried blood spot samples obtained from newborns and PKU patients. Passing Bablok analisys and Bland Altman plot analisys revealed statistically significant differences for all observed parameters. Values measured on UPLC Nexera-MS8050 tandem mass spectrometer were on average 6,5%, 2,9% and 3,5% higher compared to resultus measured on UPLC Nexera-API3200, due to higher sensitivity of UPLC Nexera-MS8050. Mean difference for Phe/Tyr ratio of 0,04 μmol/L is not considered clinically relevant and, despite constant an proportional differences in phenylalanine concentrations, we conclude that observing both phenylalanine concentrations and Phe/Tyr ratio justifies simultaneous use of examined tandem mass spectrometers for sensitive and specific newborn screening for phenylketonuria.

• Keywords: novorođenački probir; fenilketonurija; tandemska spektrometrija masa; fenilalanin; tirozin; omjer Phe/Tyr; Passing Bablok regresija; Bland Altman analiza
• Keywords (english): newborn screening; Phenylketonuria; tandem mass spectrometry; phenylalanine; tyrosine; Phe/Tyr ratio; Passing Bablok regression; Bland Altman plot
• Language: croatian
• URN:NBN: urn:nbn:hr:163:396961
• Study programme: Title: Medical biochemistry; Study programme type: university; Study level: integrated undergraduate and graduate; Academic / professional title: magistar/magistra medicinske biokemije (magistar/magistra medicinske biokemije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2018-11-28 16:14:45