Performance Characteristics - Freestyle Libre User Manual

Performance Characteristics

Clinical Study Overview
Performance of the FreeStyle Libre Flash Glucose Monitoring System (the System) was evaluated in a
clinical study. The study was conducted at 4 centers with a total of 48 subjects with diabetes (95.8%
Type 1, 4.2% Type 2). All subjects were aged eighteen and older. Subjects in the study required
insulin to manage their diabetes. Each subject wore up to two FreeStyle Libre sensors on the back
of the upper arm. During the study, subjects tested their blood glucose using fingerstick capillary
samples at least eight times during each day of the study. Subjects used the blood glucose meter
built into the FreeStyle Libre reader. Additionally, subjects had their venous blood glucose analyzed
up to 128 times over four separate visits to the clinical center. Venous blood was analyzed using
the Yellow Springs Instrument Life Sciences 2300 STAT Plus™ Glucose & Lactate Analyzer (YSI). YSI
is a laboratory glucose and lactate analyzer of whole blood and plasma and is a widely recognized
standard in laboratory analysis of blood glucose. Glucose readings obtained from the System were
compared to glucose readings obtained from the YSI to evaluate the performance of the System.
Three lots of sensors were evaluated in the study.
Agreement with YSI Levels
Agreement between FreeStyle Libre Glucose Measurement (CGM) and venous blood was characterized
by using paired CGM and Yellow Springs Instrument measurements (YSI). The accuracy of CGM versus
YSI reference was assessed by calculating the percentage of System readings that were within 15%,
20%, 30% and 40% for reference values 80 mg/dL and above, and 15 mg/dL, 20 mg/dL, 30 mg/dL and
40 mg/dL for values below 80 mg/dL when glucose levels are assigned using the YSI values. Overall
91.1% of results were within ±20 mg/dL / 20% of YSI reference.
107
ART38553-101_rev-A_manual.indd 107-108
Agreement with CGM Glucose Levels
Agreement between CGM and venous blood was characterized by using paired CGM and Yellow
Springs Instrument measurements (YSI). The accuracy of CGM versus YSI reference was assessed
by calculating the percentage of System readings that were within 15%, 20%, 30% and 40% for
reference values 80 mg/dL and above, and 15 mg/dL, 20 mg/dL, 30 mg/dL and 40 mg/dL for values
below 80 mg/dL. The results are presented in Table 1 for YSI reference. Overall 91.0% of results
were within ±20 mg/dL / 20% of YSI reference.
Table 1: Number and Percent of Results within YSI Reference
CGM Glucose Number of Within Within
Level CGM-Reference ±15% / ±20% /
(mg/dL) Pairs ±15mg/dL ±20mg/dL
Overall 5772 82.1 91.0
40-50
38 44.7 57.9
51-80 461 72.2 81.1
81-180 3236 82.9 91.2
181-300 1799 84.9 93.6
301-400 226 77.0 95.1
401-500
12 58.3 75.0
Within Within Outside
±30% / ±40% / ±40% /
±30mg/dL ±40mg/dL ±40mg/dL
97.8 99.3 0.7
81.6 94.7 5.3
92.0 97.6 2.4
97.9 99.3 0.7
99.2 99.7 0.3
99.6 99.6 0.4
100.0 100.0 0.0
108
2/1/18 2:13 PM