Interference of ascorbic acid with chemical analytes.
BACKGROUND
Ascorbic acid can interfere with methodologies involving redox reactions, while comprehensive studies on main chemistry analysers have not been reported. We therefore attempted to determine the interference of ascorbic acid with analytes on the Beckman Synchron LX20.


METHODS
Various concentrations of ascorbic acid were added to serum, and the serum analytes were measured on the LX20.


RESULTS
With a serum ascorbic acid concentration of 12.0 mmol/L, the values for sodium, potassium, calcium and creatinine increased by 43%, 58%, 103% and 26%, respectively (P<0.01). With a serum ascorbic acid concentration of 12.0 mmol/L, the values for chloride, total bilirubin and uric acid decreased by 33%, 62% and 83%, respectively (P<0.01), and were undetectable for total cholesterol, triglyceride, ammonia and lactate. There was no definite influence of ascorbic acid on analytical values for total CO(2), urea, glucose, phosphate, total protein, albumin, amylase, creatine kinase, creatine kinase-MB, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, total iron, unbound iron-binding capacity or magnesium.


CONCLUSIONS
Ascorbic acid causes a false increase in sodium, potassium, calcium and creatinine results and a false decrease in chloride, total bilirubin, uric acid, total cholesterol, triglyceride, ammonia and lactate results.
Meng
Qing H
QH
Department of Pathology, Division of Clinical Biochemistry, Royal University Hospital, College of Medicine, University of Saskatchewan, Saskatoon, SK, S7N 0W8, Canada. qing.meng@usask.ca
Irwin
William C
WC
Fesser
Jennifer
J
Massey
K Lorne
KL
D001205:Ascorbic Acid / Q000097:blood*; D001774:Blood Chemical Analysis / Q000379:methods; D004573:Electrolytes / Q000032:analysis*; D006801:Humans; D010084:Oxidation-Reduction
D004573:Electrolytes; D001205:Ascorbic Acid