Better stability of total homocysteine measurement with sodium fluoride than with EDTA.
The total homocysteine (tHcy) plasma concentration increases 10% per hour when whole blood is collected on ethylene diamine tetraacetate (EDTA) and stored at room temperature. The aim of this study was to investigate the stability of tHcy plasma concentration during 24 hours of storage at room temperature in two different collection tubes: EDTA and sodium fluoride (NaF). The evolution of tHcy plasma concentration was also compared in two different populations: healthy individuals (controls) and patients with end-stage renal failure, known to have increased plasma tHcy concentrations. Plasma was separated from erythrocytes at 0, 2, 6 and 24 hours. tHcy was measured with a competitive immunoassay on Immulite 2000 (Diagnostic Products Corporation). Plasma tHcy concentration started to rise significantly on EDTA after two hours of storage in patients and controls in comparison to baseline (defined as time: 0 hour). It remained stable on NaF during the first two hours and started to rise significantly after six hours of storage for both populations. In conclusion, NaF tubes should be preferred to EDTA tubes for tHcy determination in routine clinical chemistry laboratories.
Wolff
Fleur
F
Department of Clinical Biology, Hôpital César de Paepe, Brussels, Belgium. fleur.wolff@chu-brugmann.be
Gausset
Philippe
P
Vanderpas
Jean
J
D001793:Blood Preservation / Q000379:methods* / Q000592:standards; D004492:Edetic Acid; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D007118:Immunoassay / Q000379:methods* / Q000592:standards; D007676:Kidney Failure, Chronic / Q000097:blood; D015203:Reproducibility of Results; D012969:Sodium Fluoride
D006710:Homocysteine; D012969:Sodium Fluoride; D004492:Edetic Acid