Evaluation of the impact of hematocrit and other interference on the accuracy of hospital-based glucose meters.
BACKGROUND
Most glucose meter comparisons to date have focused on performance specifications likely to impact subcutaneous dosing of insulin. We evaluated four hospital-based glucose meter technologies for accuracy, precision, and analytical interferences likely to be encountered in critically ill patients, with the goal of identifying and discriminating glucose meter performance specifications likely to impact intensive intravenous insulin dosing.


METHODS
Precision, both within-run and day-to-day, was evaluated on all four glucose meters. Accuracy (bias) of the meters and analytical interference were evaluated by comparing results obtained on whole blood specimens to plasma samples obtained from these whole blood specimens run on a hexokinase reference method.


RESULTS
Precision was acceptable and differed little between meters. There were significant differences in the degree to which the meters correlated with the reference hexokinase method. Ascorbic acid showed significant interference with three of the four meters. Hematocrit also affected the correlation between whole blood and plasma hexokinase glucose on three of the four glucose meters tested, with the magnitude of this interference also varying by glucose meter technology.


CONCLUSIONS
Correlation to plasma hexokinase values and hematocrit interference are the main variables that differentiate glucose meters. Meters that correlate with plasma glucose measured by a reference method over a wide range of glucose concentrations and minimize the effects of hematocrit will allow better glycemic control for critically ill patients.
Karon
Brad S
BS
Department of Laboratory Medicine and Pathology, Mayo Clinic College of Medicine, Rochester Minnesota 55905, USA. Karon.bradley@mayo.edu
Griesmann
Laurie
L
Scott
Renee
R
Bryant
Sandra C
SC
Dubois
Jeffrey A
JA
Shirey
Terry L
TL
Presti
Steven
S
Santrach
Paula J
PJ
D000082:Acetaminophen / Q000494:pharmacology; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology; D001205:Ascorbic Acid / Q000494:pharmacology; D001774:Blood Chemical Analysis / Q000295:instrumentation* / Q000592:standards; D001786:Blood Glucose / Q000187:drug effects* / Q000378:metabolism*; D016638:Critical Illness; D004305:Dose-Response Relationship, Drug; D006400:Hematocrit; D006593:Hexokinase / Q000097:blood; D006801:Humans; D007328:Insulin / Q000627:therapeutic use; D007362:Intensive Care Units; D007773:Lactates / Q000494:pharmacology; D008320:Maltose / Q000494:pharmacology; D015203:Reproducibility of Results
D000894:Anti-Inflammatory Agents, Non-Steroidal; D001786:Blood Glucose; D007328:Insulin; D007773:Lactates; D000082:Acetaminophen; D008320:Maltose; D006593:Hexokinase; D001205:Ascorbic Acid