Unintended Consequence of High-Dose Vitamin C Therapy for an Oncology Patient: Evaluation of Ascorbic Acid Interference With Three Hospital-Use Glucose Meters.

The use of high-dose vitamin C in cancer care has offered promising results for some patients. However, the intravenous (IV) doses used for these patients can reach concentrations that interfere with some strip-based glucose meters. We characterized the impact of vitamin C interference, from standard to the very high doses used for some cancer protocols, using three different hospital-use glucose meters. For two of the three devices tested, increasing concentrations of ascorbic acid caused false elevations in the glucose measurements. The third glucose meter did not provide inaccurate results, regardless of the vitamin C concentration present. Rather, above a certain threshold, the device generated error messages and no results could be obtained.

Comparison of two point of care devices for capillary lipid screening in fasting and postprandial adults.

OBJECTIVES: The aim of this study was to assess the performance of two point of care (POC) devices for capillary lipid screening in fasting and post-prandial adults. DESIGN AND METHODS: Fasting and post-prandial capillary whole blood samples collected from 57 adult donors were analyzed simultaneously on Cholestech LDX Lipid Profile (Alere San Diego, Inc., San Diego, CA) cassettes and CardioChek Lipid Panel (Polymer Technology Systems, Indianapolis, IN) strips. Paired serum samples were collected from the same donors and analyzed with CDC-certified methods for total cholesterol, high density lipoprotein cholesterol (HDL-C) and non-blanked triglycerides. Non-HDL-C (total cholesterol minus HDL-C) and low density lipoprotein cholesterol (LDL-C) were calculated. Mean bias between capillary whole blood and serum laboratory lipids was calculated. RESULTS: HDL-C measurements were not affected by triglyceride content on either device. However, both devices exhibited significant variability in triglyceride measurement relative to the reference method. Compared to reference methods, Cholestech was more accurate than CardioChek for non-HDL-C while CardioChek was more accurate for HDL-C. Among the calculated cardiovascular risk parameters (LDL-C and non-HDL-C), Cholestech-calculated non-HDL-C exhibited the least average bias in both fasting and postprandial samples. CONCLUSIONS: The optimal approach to capillary lipid screening may be to use Cholestech non-HDL cholesterol; as it exhibited little bias relative to CDC reference methods in both fasting and postprandial samples, facilitating lipid screening in non-fasting adults.

Retrospective evaluation of the accuracy of Roche AccuChek Inform and Nova StatStrip glucose meters when used on critically ill patients.

BACKGROUND: More stringent accuracy guidelines for hospital-use glucose meters have recently been published, but it remains unclear whether glucose meters can meet these accuracy guidelines when measurement is performed on critically ill patients with fresh whole blood samples. MATERIALS AND METHODS: We performed a retrospective evaluation of a conventional (Roche Diagnostics [Indianapolis, IN] AccuChek® Inform) and a newer-generation (Nova Biomedical [Waltham, MA] StatStrip®) glucose system by comparing paired (drawn within 5 min of each other) whole blood glucose meter and laboratory serum glucose values obtained from intensive care unit (ICU) patients. We also performed a prospective evaluation of the accuracy of the Nova StatStrip. RESULTS: The median (interquartile range) bias between Roche AccuChek Inform and serum laboratory glucose measurements was 11 (6-18) mg/dL, compared with a median bias between the Nova StatStrip and serum glucose measurements of 1 (-5 to 5) mg/dL. StatStrip met International Organization for Standardization 15197 and Clinical and Laboratory Standards Institute (CLSI) POCT12-A3 accuracy guidelines using both retrospective and prospective datasets. CONCLUSIONS: The newer-generation (StatStrip) glucose meter met more stringent CLSI POCT12-A3 accuracy criteria because of reduced bias compared with the previous-generation device. Reduced glucose meter bias led to fewer insulin dosing discrepancies when the insulin dose determined from serum glucose was compared with that determined from the glucose meter value using the institutional glycemic control protocol.