Abstract
Free Style Libre Pro, a novel continuous glucose monitoring (CGM) device for retrospective assessment of glycemic excursion, does not require calibration during the measurement period. In this study, the accuracy of FreeStyle Libre Pro in normal glucose levels was investigated. Two meal tests, on the 7th day and 9th day of CGM usage, were performed in five non-diabetic adults. Venous blood samples were obtained at baseline, and at 2 hours, 4 hours and 6 hours after the meal. The plasma glucose levels and the glucose levels measured by FreeStyle Libre Pro were compared. Subjects were aged 41.4±7.6 years, 40% male, with body mass index 21.7±2.6, HbA1c 5.6±0.3% and a fasting plasma glucose level of 95.4±2.1 mg/dl. The plasma glucose levels and the glucose levels measured by FreeStyle Libre Pro were significantly different; 94.4±1.8 vs. 111.2±8.5 mg/dl (P <0.01) at baseline, 95.6±7.0 vs. 122.6±8.8 mg/dl (P <0.01) at 2 hours, 90.1±4.3 vs. 111.2±13.0 mg/dl (P <0.01) at 4 hours, and 88.7±3.2 vs. 105.5±7.1 mg/dl (P <0.01) at 6 hours. The absolute difference between the two methods was 17.7±7.5 (minimum 5 - maximum 27) mg/dl at baseline, 27.0±9.4 (minimum 8 - maximum 40) mg/dl at 2 hours, 21.1±11.3 (minimum 7 - maximum 42) mg/dl at 4 hours, 16.8±5.4 (minimum 7 - maximum 23) mg/dl at 6 hours, and 20.7±9.3 (minimum 5 - maximum 42) mg/dl for all time points, respectively. The absolute relative difference between them was 18.7±7.8 (minimum 5.3 - maximum 28.7)% at baseline, 28.7±10.7 (minimum 7.7 - maximum 45.5)% at 2 hours, 23.3±12.2 (minimum 7.9 - maximum 45.2)% at 4 hours, 18.9±6.0 (minimum 8.0 - maximum 26.2)% at 6 hours, and 22.4±10.0 (minimum 5.3 - maximum 43.5)% for all time points, respectively. The ratio of values measured by FreeStyle Libre Pro within the interval of ±15 mg/dl in less than 100 mg/dl or within the interval of ±15% in not less than 100 mg/dl plasma glucose levels was 30.0% at baseline, 10.0% at 2 hours, 40.0% at 4 hours, 50.0% at 6 hours and 32.5% for all time points, respectively. These study results suggest FreeStyle Libre Pro may not be sufficiently accurate in normal glucose levels.
Highlights
Continuous glucose monitoring (CGM) is a technology to monitor blood glucose levels continuously in humans, especially in patients with diabetes mellitus [1,2,3]
LP: glucose levels measured by FreeStyle Libre Pro
Despite the small sample size, the glucose levels measured by FreeStyle Libre Pro were significantly higher than plasma glucose levels, and the ratio of the measurement within the interval of ±15 mg/dl in less than 100 mg/dl or within the interval of ±15% in not less than 100 mg/dl plasma glucose levels, one of the well-accepted criteria of accuracy equivalent to ISO 15197:2013 standard used for the evaluation of conventional systems for self-monitoring of blood glucose (SMBG), was far below 95%
Summary
Continuous glucose monitoring (CGM) is a technology to monitor blood glucose levels continuously in humans, especially in patients with diabetes mellitus [1,2,3]. The early prototype of CGM was introduced in 1977 as a part of a device called “Biostator” intended to be used as an artificial pancreas [4] This original method required taking small volume blood samples from the patient continuously, making the device unsuitable for long time usage in daily life. The ISO 15197:2013 standard demands at least 95% of the values obtained by SMBG devices are within the interval of ±15 mg/dl in less than 100 mg/dl or within the interval of ±15% in not less than 100 mg/dl plasma glucose levels. For patients with type 1 diabetes mellitus, ISO 15197:2013 standard demands at least 99% of the values obtained by SMBG devices are in Zone A and Zone B of the Consensus Error Grid [8]. SMBG has been used for adjusting insulin dosage, and for modifying lifestyle by providing feedback to patients regarding the effect of diet and exercise on blood glucose levels
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
