Sensor Glucose vs Blood Glucose
Finger prick blood glucose readings and sensor glucose reading won't always match and in fact are likely to be different.
That's because sensor glucose readings come from the interstitial fluid (ISF), a thin layer of fluid that surrounds the cells of the tissues below your skin, not from your blood.
There is a 5 to 10 minute delay in ISF glucose response to changes in blood glucose.79 Glucose readings on ISF have been proven to reliably reflect glucose levels.80
When glucose levels remain stable..
...the glucose levels recorded by the FreeStyle Libre 2 Plus sensor and blood glucose are similar, though not always exactly the same.
With rapidly rising glucose levels..
...the glucose levels recorded by the FreeStyle Libre 2 Plus sensor may be lower than blood glucose levels.
For rapidly falling glucose...
...the glucose levels recorded by the FreeStyle Libre 2 Plus sensor may be higher than the blood glucose levels.
How does the sensor reading compare with a blood glucose reading?
Traditional Blood Glucose Monitoring
Measures the glucose levels in the blood (capillary).
- A lancet is inserted to reach the blood in the capillary.
- A finger prick only provides one measurement at one point in time.
- Requires a whole kit: lancets (finger pricker), blood glucose strips, and blood glucose reader.
The FreeStyle Libre 2 Plus system
Continuously measures the glucose levels in the interstitial fluid (ISF): the fluid between the cells under the skin.
- Glucose readings based on interstitial fluid have been shown to reliably reflect glucose levels.
- The sensor is painless to apply and wear, with zero finger pricks.12
- The sensor takes a glucose reading every minute and automatically displays it on your phone.55
Glucose reading vs sensor reading
Here's a video tutorial to help show how blood glucose readings are different to sensor readings