Accuracy of whole blood glucose measurement when venous catheter blood samples are used on glucose meters.
BACKGROUND
Previous studies have found positive bias and frequent outliers when central venous catheter (CVC) whole blood is used to dose glucose meters. We designed a study to determine whether positive bias and outliers with CVC whole blood glucose samples are due to exogenous glucose contamination of CVC samples, inherent bias and imprecision of glucose meters, or properties of CVC whole blood that interfere with the function of some glucose meters.


METHODS
We studied the relationship between venous whole blood and venous plasma glucose drawn by venipuncture to CVC whole blood and CVC plasma glucose in 50 hospitalized patients. In 27 patients whole blood glucose was measured on both the Accu-Chek Inform (Roche Diagnostics, Indianapolis, IN) and StatStrip (Nova Biomedical, Waltham, MA).


RESULTS
By comparing CVC plasma to venous plasma glucose, we determined that contamination of CVC samples with exogenous glucose was uncommon. On the Inform meter outliers were approximately twice as common with CVC whole blood compared to venous whole blood. In 27 patients who had CVC whole blood analyzed by both Inform and StatStrip, outliers occurred approximately twice as often on the Inform compared to the StatStrip. Accounting for CVC samples contaminated with exogenous glucose, outliers on the StatStrip did not occur significantly more often using CVC whole blood compared to venous whole blood.


CONCLUSIONS
Properties unique to CVC whole blood differentially affect glucose meter bias and imprecision. Device selection is critical in practices that wish to use CVC whole blood to monitor glucose concentration in hospitalized patients.
Karon
Brad S
BS
Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota 55905, USA. Karon.bradley@mayo.edu
Koch
Christopher D
CD
Wockenfus
Amy M
AM
Brown
Julie K
JK
D001774:Blood Chemical Analysis / Q000295:instrumentation* / Q000379:methods; D001786:Blood Glucose / Q000032:analysis*; D002405:Catheterization, Central Venous / Q000379:methods*; D003920:Diabetes Mellitus / Q000097:blood; D005260:Female; D006801:Humans; D007297:Inpatients; D008297:Male; D018962:Phlebotomy / Q000379:methods*; D019095:Point-of-Care Systems; D015203:Reproducibility of Results
D001786:Blood Glucose