Korean Diabetes J.  2010 Dec;34(6):350-358. 10.4093/kdj.2010.34.6.350.

The Correlation and Accuracy of Glucose Levels between Interstitial Fluid and Venous Plasma by Continuous Glucose Monitoring System

• Baek YH
• Jin HY
• Lee KA
• Kang SM
• Kim WJ
• Kim MG
• Park JH
• Chae SW
• Baek HS
• Park TS

• KMID: 2222362
• DOI: http://doi.org/10.4093/kdj.2010.34.6.350

Abstract

BACKGROUND
Clinical experience with the continuous glucose monitoring systems (CGMS) is limited in Korea. The objective of this study is to evaluate the accuracy of the CGMS and the correlation between interstitial fluid and venous plasma glucose level in Korean healthy male subjects.
METHODS
Thirty-two subjects were served with glucose solution contained same amount of test food's carbohydrate and test foods after separate overnight fasts. CGMS was performed over 3 days during hopitalization for each subjects. Venous plasma glucose measurements were carried out during 4 hours (0, 0.25, 0.5, 0.75, 1, 2, 4 hours) just before and after glucose solution and test food load. The performance of the CGMS was evaluated by comparing its readings to those obtained at the same time by the hexokinase method using the auto biochemistry machine (Hitachi 7600-110). Also, correlations between glucose recorded with CGMS and venous plasma glucose value were examined.
RESULTS
CGMS slightly underestimated the glucose value as compared with the venous plasma glucose level (16.3 +/- 22.2 mg/dL). Correlation between CGMS and venous plasma glucose values throughout sensor lifetime is 0.73 (regression analysis: slope = 1.08, intercept = 8.38 mg/dL). Sensor sensitivity can deteriorate over time, with correlations between venous blood glucose and CGMS values dropping from 0.77 during 1st day to 0.65 during 2nd and 3rd day.
CONCLUSION
The accuracy of data provided by CGMS may be less than expected. CGMS sensor sensitivity is decreased with the passage of time. But, from this study, CGMS can be used for glucose variability tendency monitoring conveniently to the Korean.

Keyword

Continuous glucose monitoring system; Extracellular fluid; Plasma

MeSH Terms

Biochemistry
Blood Glucose
Extracellular Fluid
Glucose
Hexokinase
Humans
Korea
Male
Plasma
Reading
Blood Glucose
Glucose
Hexokinase

Figure

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  Fig. 1 (A) group 1, (B) group 2, (C) group 3, and (D) group 4. The relation between continuous glucose monitoring system (CGMS) and venous blood glucose levels according to the subject groups. CGMS slightly underestimated the glucose value as compared with the venous plasma glucose level. "Time-lag" is observed. However, between each group were similar to venous glucose and CGMS aspects. Data was shown as mean ± standard deviation. Rc: Control , Rt: Test meal (R: Glucose from CGMS vs. Blood plasma glucose).

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  Fig. 2 (A) Korean meal 1, (B) Korean meal 2, (C) Western meal 1, and (D) Western meal 2. The relation between continuous glucose monitoring system (CGMS) and venous plasma glucose levels according to the meals. When compared by each diet, venous glucose and CGMS levels showed similar patterns that did not differ significantly. Data was shown as mean ± standard deviation. Rc: Control , Rt: Test meal (R: Glucose from CGMS vs. Blood plasma glucose).

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  Fig. 3 The glucose levels measured by continuous glucose monitoring system between controls (O) and treatment (Δ) groups according to the time passage.

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  Fig. 4 Correlation between continuous glucose monitoring system (CGMS) and venous plasma glucose levels (regression analysis: slope = 1.08, intercept = 8.38 mg/dL).

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  Fig. 5 Correlation between continuous glucose monitoring system (CGMS) and venous plasma glucose levels (1st day, regression analysis: slope = 1.08, intercept = 8.38 mg/dL).

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  Fig. 6 Correlation between continuous glucose monitoring system (CGMS) and venous plasma glucose levels (2nd day, regression analysis: slope = 1.08, intercept = 8.38 mg/dL).

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  Fig. 7 Correlation between continuous glucose monitoring system (CGMS) and venous plasma glucose levels using the Clarke error grid analysis (n = 1,568); 95.4% measures were within zones A and B.

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