Assessment of trueness of a glucose monitor using interstitial fluid and whole blood as specimen matrix.
BACKGROUND
Interstitial fluid (ISF) is a specimen of increasing interest for glucose measurements because it can be obtained in a minimally invasive manner. Our previous study showed that sufficient ISF can be obtained using microneedles to measure glucose with a conventional electrochemical glucose monitor. The aim of this study was to assess the trueness of this glucose monitor using split-sample comparison with whole blood. We used ISF as specimen and our gas chromatography/mass spectrometry (GC/MS) method as reference.


METHODS
We obtained 50 ISF samples and 40 whole blood samples from hairless Sprague- Dawley rats and analyzed for glucose by both methods.


RESULTS
For whole blood, a non-significant bias of 5.7% (+/-2 SD: -54.9% to 66.3%) was determined. ISF glucose measurements showed a significant constant bias of 29.5% (+/-2 SD: -85.0% to 144%), which seems to be caused in part by the lack of red blood cells in ISF. The correlation coefficients were 0.782 and 0.679 for whole blood and ISF, respectively.


CONCLUSIONS
The assessed electrochemical glucose monitor shows a close agreement with our GC/MS reference method for whole blood, for which this monitor was optimized. When glucose measurements are performed with ISF as matrix, the observed bias needs to be taken into consideration. Further studies are necessary to elucidate the reasons for the wide dispersion of data for ISF.
Vesper
Hubert W
HW
Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Georgia Institute of Technology, Atlanta, Georgia 30341, USA. HVesper@cdc.gov
Wang
Ping M
PM
Archibold
Enada
E
Prausnitz
Mark R
MR
Myers
Gary L
GL
D000818:Animals; D001786:Blood Glucose / Q000032:analysis*; D045604:Extracellular Fluid / Q000737:chemistry*; D005947:Glucose / Q000032:analysis*; D008297:Male; D023421:Models, Animal; D008991:Monitoring, Physiologic / Q000379:methods*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results
D001786:Blood Glucose; D005947:Glucose