Dried blood spot versus venous blood sampling for phenylalanine and tyrosine.
Kimber van VlietWiggert G van GinkelEsther van DamPim de BlaauwMartijn KoehorstHermi A KingmaFrancjan J van SpronsenMargaretha Rebecca Heiner-FokkemaPublished in: Orphanet journal of rare diseases (2020)
Overall agreement between plasma and DBS is good. However, bias is specimen- (LH vs EDTA), and possibly concentration- (low phenylalanine) dependent. Because of the overall good agreement, we recommend the use of a DBS-plasma correction factor for DBS measurement. Each laboratory should determine their own factor dependent on filter card type, extraction and calibration protocols taking the LH plasma values as gold standard.
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