Interference with the Measurement of Blood Glucose in Different Systems after Intravenous High Dose Ascorbic Acid Supplement

Moon, Hee Won; Kim, Jae Young; Kang, Eun Suk; Chung, Wha Soon

Abstract

BACKGROUND
Intravenous administration of high doses of ascorbic acid (AA) for certain clinical conditions can cause high levels of blood AA to interfere with the measurement of blood glucose. In this study, we evaluated the potential interference by high concentrations of blood AA with glucose measurement in different instruments. METHODS: Using Hitachi 7600 chemistry autoanalyzer (Hitachi 7600) and Accu-Chek Active monitor glucometer (Accu-Check), glucose was measured in serum specimens in which AA had been added in vitro at concentrations ranging from 0 to 28, 388 micromol/L. To assess the effect of pharmacokinetics of AA on glucose concentrations, blood AA and glucose were measured serially in healthy subjects after 10 g of IV Vitamin C supplement was administered. RESULTS: Beginning at the concentration of 227 micromol/L, the blood AA interfered with glucose measurement negatively in Hitachi 7600, but positively in Accu-Chek. The extent of interference was proportional to AA concentrations in both directions. The in vivo study showed that, although both instruments were affected by high blood AA at 1 hour of IV administration, blood glucose levels were normalized at 5 hours in Hitachi 7600 and at 3 hours in Accu-Chek. CONCLUSIONS: When considering that IV high dose AA supplement is becoming more popular and the extent of its interference with blood glucose measurement is significantly high in commercial systems, it would be important for the clinical laboratory to be informed of the prescription informations of patients and the time of blood collection, and to choose a correct system for an accurate blood glucose measurement.