How Does The Sensor Work - Freestyle Libre User Manual

How does the sensor work?

How does the sensor
measure glucose?
When you apply the FreeStyle Libre
sensor, a thin filament is inserted under
your skin and measures glucose levels.
What does the sensor measure?
The sensor measures the glucose levels
in the interstitial fluid (ISF)—a fluid that
surrounds the cells beneath your skin—
instead of blood glucose.
TIPS TO REMEMBER
It can take a few moments
for glucose to move from
blood to the ISF
Blood glucose readings
5
tend to be about 5 minutes
ahead of sensor readings
For illustrative purposes only. Image not drawn to scale.
* A finger prick test using a blood glucose meter is required during times of rapidly changing glucose levels when interstitial fluid glucose levels may not accurately
reflect blood glucose levels or if hypoglycemia or impending hypoglycemia is reported by the system or when symptoms do not match the system readings.
† Treatment decisions should not be based on real-time sensor glucose readings alone but instead should consider all the information on the results screen.
Reference: 1 Bailey T, Bode BW, Christiansen MP, Klaff LJ, Alva S. The performance and usability of a factory-calibrated flash glucose monitoring system. .
Diabetes Technol Ther. 2015;17(11):787-794.
Skin
ISF
Your trend arrow tells you
what direction your glucose
is heading
For most treatment
decisions, sensor readings
from the FreeStyle Libre
1
system can replace
finger-prick tests*
Cells
Glucose Capillary
,†
8