User Manual

84 Chapter 5
Performance Results
The performance of the Guardian RT was evaluated in a clinical study. Guardian RT results were compared to
plasma glucose values from a reference method, the YSI 2300 STAT Plus
TM
glucose analyzer (referred to as
YSI). Sixteen subjects with Type I diabetes participated in a single-site in-clinic study. Subjects ranged in age
from 18 to 65 years old. Each subject wore 2 Guardian RT systems simultaneously. One Guardian system was
calibrated an average of 3.5 times per day, and the other was calibrated approximately 5 times per day using
the BD Logic
TM
meter. YSI measurements were taken every thirty minutes.
Users and their healthcare providers should consider that performance in this study may be idealized, and
that performance may be worse when the Guardian RT is used in a less-controlled home setting. For
example:
‡ The mean Hemoglobin A1c among the 16 participants was 8.2%. As hemoglobin A1c levels rise,
conditions often occur which are most challenging to test systems measuring glucose in interstitial
fluid, i.e., higher glucose levels, more rapid changes in glucose concentrations, and often more
hypoglycemic episodes.
‡ Subjects saw, on average, between 4 and 5 fingerstick values per day. This enables subjects to
better manage their diabetes when compared to those who perform less fingersticks per day.
Agreement between Guardian RT and YSI values is shown to be closer at mid-range glucose levels,
as compared to agreement at low or high glucose concentrations.
‡ Subjects were more limited in their activities than what may exist in home use, and they were
provided with all their meals. Sensors were also inserted by clinic staff rather than the subjects
themselves. Subjects who are more active, or with poor eating habits, may create more challenging
conditions for the Guardian RT.
‡ Performance of the Guardian RT may vary depending on the glucose meter used and how well the
meter is maintained. It is important to carry out quality-control checks on the meter and code the
meter according to the manufacturer's instructions to optimize performance of the Guardian RT.