Performance Characteristics
Clinical Study Overview
Performance of the FreeStyle Libre Pro Flash Glucose Monitoring System (the System) was
evaluated in a clinical study. The study was conducted in 4 centers; a total of 72 subjects with
diabetes (81.9% Type 1, 18.1% Type 2) aged eighteen and older were included in the study; all
subjects required insulin administration either by an insulin pump or via multiple daily injections
to manage their diabetes. Each subject wore two sensors for up to 14 days, one on the back of
each upper arm. During the study, subjects tested their blood glucose using fingerstick capillary
samples using a FreeStyle Precision blood glucose meter. Additionally, subjects had their venous
blood glucose analyzed approximately 96 times over three separate visits to the clinical center
using the Yellow Spring Instrument Life Sciences 2300 STAT Plus™ Glucose & Lactate Analyzer
(YSI). YSI is a laboratory-grade 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 GM and venous blood was characterized by using paired GM and plasma
equivalent Yellow Springs Instrument measurements (YSI).
The accuracy of GM 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. The results are presented in
Table 1
. Overall 83.8% of results
were within ±20 mg/dL / 20% of YSI reference.
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