Pilot Experience with an External Quality Assurance Scheme for Acylcarnitines in Plasma/Serum

Abstract

The analysis of acylcarnitines (AC) in plasma/ serum is established as a useful test for the biochemical diagnosis and the monitoring of treatment of organic acidurias and fatty acid oxidation defects. External quality assurance (EQA) for qualitative and quantitative AC is offered by ERNDIM and CDC in dried blood spots but not in plasma/serum samples. A pilot interlaboratory comparison between 14 European laboratories was performed over 3 years using serum/plasma samples from patients with an established diagnosis of an organic aciduria or fatty acid oxidation defect. Twenty-three different samples with a short clinical description were circulated. Participants were asked to specify the method used to analyze diagnostic AC, to give quantitative data for diagnostic AC with the corresponding reference values, possible diagnosis, and advice for further investigations.Although the reference and pathological concentrations of AC varied among laboratories, elevated marker AC for propionic acidemia, isovaleric acidemia,

Biochemical Markers for the Diagnosis of Mitochondrial Fatty Acid Oxidation Diseases

“…The correct diagnosis of patients has been difficult for many years, since there has been a lack of adequate biomarkers in the blood, serum or plasma, and of enzymatic assays that allow the specification of a definite FAOD [ 17 ]. The use of tandem mass spectrometry at the end of the 20th century manifested great changes via improvements in acylcarnitine analysis, and quality control schemes are now well-established [ 18 ]. This biochemical method has now become the main choice for the diagnosis of FAODs, revolutionizing newborn screening with its implementation.…”