How the FreeStyle Libre works
The FreeStyle Libre works by having a small round sensor applied to your arm.
The sensor is a round disc, 5mm high and 35mm diameter, making it roughly the size of a £2 coin.
The sensor is applied to the skin with a handheld applicator and then lasts for 14 days. Most people that were used in patient trials of the Libre rated the application of the sensor as being painless.
Within the 14 days of usage, the sensor allows you to scan the sensor with the handset which sends data of your sugar levels over the previous 8 hours to the Libre systems handset.
When you scan, you therefore get not just a glucose reading, as you would with a blood glucose meter, but can also see whether your sugar levels are starting to go up, down or are stable.
Technical specifications (reader)
Radio frequency: 13.56 MHz
Data port: Micro USB
Blood glucose measurement range: 1.1 to 27.8 mmol/L
Blood ketone measurement range: 0.0 to 8.0 mmol/L
Battery: 1 lithium-ion rechargeable battery
Battery life: 7 days typical usage between charging
Service life: 3 years of typical use
Dimensions: 95 x 60 x 16 mm
Weight: 65 g
Operating and storage ranges
Operating temperature: 10° to 45°C
Storage temperature: -20° to 60°C
Altitude: -381 m (-1, 250 ft) to 3, 048 m (10, 000 ft)
Technical specifications (sensors)
Memory: 8 hours (32 readings)
Sensor life: Up to 14 days
Battery: 1 silver oxide battery (lasts the life of the sensor)
Dimensions: 35 mm diameter and 5 mm height
Weight: 5 g
