User guide

Performance results in adults
The performance of the Guardian RT in adults was evaluated in a clinical study.
3
Guardian RT results were
compared to plasma glucose values from a reference method, the YSI 2300 STAT Plus™ 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 two Guardian RT systems
simultaneously. One Guardian system was calibrated an average of 3.5 times per day, and the other was
calibrated approximately five times per day using the Paradigm Link blood glucose meter. YSI
measurements were taken every 30 minutes.
Users and their healthcare professionals 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 percent. 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 four and five 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.
Accuracy of Guardian RT readings
In this study, YSI measurements (taken every half hour) were paired with the corresponding Guardian RT
reading (taken every five minutes). Pairing was done by selecting the Guardian RT value closest in time to
the YSI test result. Agreement was analyzed by comparing paired glucose measurements.
3. Medtronic Diabetes, A Frequent Sample Accuracy Evaluation of the Medtronic Diabetes Telemetered Glucose Monitoring
System II (TGMS II) in Subjects with Type 1 Diabetes Mellitus, August 2004.
Appendix A134