Monitoring phenylalanine concentrations in the follow-up of phenylketonuria patients: An inventory of pre-analytical and analytical variation.
Karlien L M CoeneCorrie TimmerSusan M I GoordenAmber E Ten HoedtLeo A J KluijtmansMirian C H JanssenAlexander J M RenningsHubertus C M T PrinsenMirjam M C WamelinkGeorge J G RuijterIrene M L W Körver-KeulartsM Rebecca Heiner-FokkemaFrancjan J van SpronsenCarla E HollakFrédéric M VazAnnet M BoschMarleen C D G HuigenPublished in: JIMD reports (2020)
The results of our study point to substantial (pre-)analytical variation in Phe measurements, implicating that bloodspot Phe results should be interpreted with caution, especially when no correction factor is applied. To minimize variation, we advocate pre-analytical standardization and analytical harmonization of Phe measurements, including consensus on application of a correction factor to adjust DBS Phe to plasma concentrations.