Synthetic calibrators for the analysis of total metanephrines in urine: revisiting the conditions of hydrolysis.

Details

Ressource 1Request a copy Sous embargo indéterminé.
State: Public
Version: author
Serval ID
serval:BIB_F4DA47379F47
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Synthetic calibrators for the analysis of total metanephrines in urine: revisiting the conditions of hydrolysis.
Journal
Clinica Chimica Acta
Author(s)
Simonin J., Gerber-Lemaire S., Centeno C., Seghezzi C., Iglesias K., Abid K., Grouzmann E.
ISSN
1873-3492 (Electronic)
ISSN-L
0009-8981
Publication state
Published
Issued date
2012
Peer-reviewed
Oui
Volume
413
Number
11-12
Pages
998-1003
Language
english
Notes
Publication types: Journal Article ; Research Support, Non-U.S. Gov'tPublication Status: ppublish
Abstract
BACKGROUND: The quantification of total (free+sulfated) metanephrines in urine is recommended to diagnose pheochromocytoma. Urinary metanephrines include metanephrine itself, normetanephrine and methoxytyramine, mainly in the form of sulfate conjugates (60-80%). Their determination requires the hydrolysis of the sulfate ester moiety to allow electrochemical oxidation of the phenolic group. Commercially available urine calibrators and controls contain essentially free, unhydrolysable metanephrines which are not representative of native urines. The lack of appropriate calibrators may lead to uncertainty regarding the completion of the hydrolysis of sulfated metanephrines, resulting in incorrect quantification.
METHODS: We used chemically synthesized sulfated metanephrines to establish whether the procedure most frequently recommended for commercial kits (pH 1.0 for 30 min over a boiling water bath) ensures their complete hydrolysis.
RESULTS: We found that sulfated metanephrines differ in their optimum pH to obtain complete hydrolysis. Highest yields and minimal variance were established for incubation at pH 0.7-0.9 during 20 min.
CONCLUSION: Urinary pH should be carefully controlled to ensure an efficient and reproducible hydrolysis of sulfated metanephrines. Synthetic sulfated metanephrines represent the optimal material for calibrators and proficiency testing to improve inter-laboratory accuracy.
Keywords
Adrenal Gland Neoplasms/urine, Calibration, Humans, Hydrogen-Ion Concentration, Hydrolysis, Metanephrine/chemical synthesis, Metanephrine/chemistry, Pheochromocytoma/urine, Sulfates/chemistry, Uncertainty
Pubmed
Web of science
Create date
19/05/2012 19:34
Last modification date
20/08/2019 17:21
Usage data