FreeStyle Libre Sensor

What is the FreeStyle Libre Sensor system?

The FreeStyle Libre Sensor system is a flash glucose monitoring system. It quickly scans the amount of glucose in the blood without the need for a traditional finger-prick test.

For people with diabetes, who need their blood glucose levels monitored on a daily basis, it can make the process faster, easier, less invasive and painless.

In people with diabetes, glucose (sugar) struggles to reach the cells that need it for energy due to an impairment or lack of insulin. Insulin is a hormone that helps transfer glucose from the bloodstream into cells.

Unlike traditional finger-prick monitors, which measure the amount of glucose in the blood, the FreeStyle Libre system measures the glucose in the interstitial fluid.

While cells are packed tightly together, they reside in a substance called interstitial fluid - the word interstice means a small space or gap. The glucose exits the bloodstream and enters the interstitial fluid. From there, insulin, which binds to the cell's membrane receptors, transports the glucose from the interstitial fluid and into the cell.

The FreeStyle Libre Sensor continuously tracks the changes in the amount of glucose present in the interstitial fluid. By scanning the sensor with a reader (not included) or an NFC-enabled smartphone, you can check whether your blood sugar levels are rising or falling, allowing you to manage your condition more effectively.

You should speak to your doctor or diabetes nurse before you buy FreeStyle Libre online. They will be able to help you determine whether the FreeStyle Libre Sensor system is suitable for you and your lifestyle. Furthermore, your doctor may wish to track your blood glucose levels remotely - your doctor will discuss this with you.

You can buy the FreeStyle Libre Sensors online from Prescription Doctor following an online consultation.

How does the FreeStyle Libre Sensor system work?

The FreeStyle Libre system utilises near field communication (NFC) to wirelessly transmit data about your blood glucose levels. The FreeStyle Libre system consists of two parts: the Sensor and the Reader.

The Sensor

The Sensors are small plastic disks, about the size of a £2 coin, which are affixed to the rear of the upper arm with an adhesive backing. The adhesive keeps the sensor in place, preventing it from falling off.

Each sensor has a small, thin, flexible fibre which penetrates 5mm into the skin. The fibre is a mere 0.4mm in diameter. In studies, most people reported that they couldn't feel the needle once it was applied. The fibre monitors the interstitial fluids which surround cells to track the changes in glucose levels. Interstitial fluids can give a good indication of how much glucose is being used by the cells.

Scanning the sensor three times a day will provide a 24-hour picture of your blood glucose levels, although you can scan the sensor as often as you'd like. The sensor can store up to 8 hours of data.

Unlike finger-prick test strips (sometimes referred to as fingersticks), the FreeStyle Libre Sensors are factory-calibrated and ready for use immediately. Due to the manufacturing process, the sensors are very accurate, and there is little deviation in accuracy from one FreeStyle Libre Sensor to the next.

The Reader (sold separately)

The sensor is scanned with a special reader, which provides a graphical indication of your blood sugar levels. To scan the sensor using the reader, simply hold the reader approximately 1 to 4 centimetres above the sensor for a second. The sensor can even be scanned through clothing.

The Reader has a colour, backlit, touchscreen display. Not only is the screen easy to view in low light, but it's also intuitive to use.

When you scan the sensor using the reader, the data will appear, including the current blood glucose level (in mmol), whether your blood glucose level is rising or falling, a graph showing your previous blood sugar levels, and even an estimated indication of how much insulin remains in your body. You can also add further information about the reader, including notes on what you ate or exercise you did, and whether you are taking long-acting or short-acting insulin.

If the device suspects hypo- or hyperglycaemia, you should confirm this is the case with a traditional finger-prick blood glucose test. At the base of the reader, you'll find a FreeStyle Neo test strip port, which is compatible with FreeStyle Optium test strips.

On the front of the device, you'll find a single blue button which is used to interface with the reader. The button serves as both a "home" and "back" button, while also acting as the power button to turn the reader on and off.

The Reader features a rechargeable lithium-ion battery that can be charged via the micro-USB port located on the side of the unit. Under normal use, the internal battery lasts for 7 days.

Smartphone Compatibility

If you have an NFC-enabled smartphone, you can use the FreeStyle LibreLink mobile app to scan your sensor. The FreeStyle LibreLink app contains the same features as the FreeStyle Libre Reader, minus the ability to read FreeStyle Optium test strips.

See the table below for supported devices.

To use your smartphone to scan the sensor, open the FreeStyle LibreLink app and hover your smartphone between 1cm and 5cm above the sensor. Your reading should appear on your phone screen.

You can use the app to add notes and view changes just like on the reader.

How to use the FreeStyle Libre flash glucose monitoring system?

Using the FreeStyle Libre flash glucose monitoring system is relatively easy. Full instructions on how to use the sensors and reader can be found in the supporting documentation supplied with the device. You should retain the instructions for future reference.

A starter pack is available, which contains everything you need, including:

• Alcohol wipes
• FreeStyle Libre Reader
• FreeStyle Libre Sensors
• FreeStyle Libre sensor applicator
• Micro-USB power cable (for charging the FreeStyle Libre Reader)
• Quick start guide

Watch the tutorial below to see how easy it is to get started using the FreeStyle Libre flash glucose monitoring system.

Applying the sensor

Sensors are applied using a special applicator, which is supplied with the sensors.

The sensor should be applied to clean and clear skin.

Avoid applying the sensor to oily skin. If your skin is oily, use soap and water to wash the application site, then wipe it down with an alcohol wipe and allow the area to dry.

Ensure the application site is void of cuts, scratches or other lesions.

Body hair can become caught between the adhesive and the skin, making it difficult to apply and remove the sensor. Therefore, it is recommended to shave the area before attaching the sensor.

Further information about how to use your FreeStyle Libre 2 System.

Here's how to apply the sensor:

1. Find a suitable site for the sensor. It is recommended to use the rear of the upper arm. You may find it easier to place the sensor on your non-dominant arm. If you are right-handed, place the sensor on your left arm.
2. Clean the site with an alcohol wipe and wait for the area to dry. Do not blow on the area to speed up the drying process.
3. Verify that the 3-digit sensor code on the sensor pack matches the one on the applicator. Do not use if the sensor pack is damaged or already opened.
4. Peel the lid off the sensor pack completely and unscrew the cap from the sensor applicator.
5. Line up the dark marks on the applicator with the dark marks on the sensor pack and press down firmly on a hard surface (such as a table) until the applicator comes to a complete stop.
6. Lift the sensor applicator out of the sensor pack. Your sensor application is ready to apply the sensor.
7. Place the sensor applicator over the application site and press down firmly to apply the sensor. Do not push down on the sensor applicator until it is placed over the prepared site to prevent unintended results or injury.
8. Gently pull the sensor applicator away.
9. Ensure the sensor is secure and discard the used sensor applicator into a sharps bin.

The sensor has a 1-hour warm-up period. This means that you should wait an hour after applying the sensor before taking a reading. The sensor may not produce an accurate reading during this time.

You should keep the sensor on your arm for 14 days (2 weeks).

For further information on how to apply the sensor, please refer to the supporting literature provided with your product.

Scanning the sensor using the reader or smartphone

Once the sensor is applied, scanning it is easy.

Start by turning on the reader (by pressing the button on the front of the device) or launching the mobile app.

If the sensor is newly applied, you will need to tap "Start new sensor".

To scan the sensor, simply hold the device (FreeStyle Libre Reader or NFC-enabled smartphone) 4cm above it. The device should show the reading.

You should scan the sensor at least once every 8 hours, though it is often recommended to scan the sensor 6 times a day to keep track of your blood sugar levels.

Removing the sensor

You should replace your sensor after 14 days (2 weeks).

To remove your sensor, gently lift the edge of the adhesive pad and slowly peel away the sensor in one smooth motion. Do not rip the sensor off quickly.

You may notice some residual glue left over once the adhesive pad has been removed. This remaining adhesive can be removed with baby oil, UNI-SOLVE Adhesive Remover, or Remove Adhesive Remover.

Discard the sensor in a sharps bin. Do not dispose of the sensor in general household waste or water.

Frequently asked questions

What should I do if I forget to apply a FreeStyle Libre Sensor when I should?

If you forget to apply the sensor when you should, apply it as soon as you remember.

What should I do if the FreeStyle Libre Sensor falls off?

If your sensor comes loose, simply apply a new sensor and scan it again. The device will recognise it as a new sensor.

Can the FreeStyle Libre Sensor be used on patients who are on dialysis or fitted with pacemakers?

FreeStyle Libre Sensors have not been evaluated for use in patients on dialysis or those with pacemakers. If either of these situations applies to you, speak to your doctor first before you buy a FreeStyle Libre Sensor system online.

How long should I leave the FreeStyle Libre Sensor on for?

The sensor is kept on for 14 days (2 weeks). After 14 days, you should remove the sensor and apply a new one.

Where on the body can the sensor be worn?

You can only wear the sensor on the back of the upper arm. You may find it easier to place the sensor on your non-dominant arm to facilitate scanning.

Will I be able to feel the sensor inside me?

In studies, most users reported being unable to feel the needle of the sensor inside them. They also noted that it didn't feel uncomfortable.

How accurate is the sensor?

The FreeStyle Libre Sensor is very accurate in most situations. However, a finger-prick glucose test may be required in cases of rapidly changing blood glucose levels or when your symptoms do not match the sensor reading.

How many glucose readings can be taken with the FreeStyle Libre Sensor?

You can take as many readings of the sensor as you want. For a full 24-hour glycaemic picture, you should scan the sensor at least once every 8 hours.

How do I dispose of a FreeStyle Libre Sensor after removing it?

The sensor packaging can be discarded in general waste. However, both the sensor itself and the sensor applicator contain needles and must be discarded safely in a sharps bin.

Can I shower, exercise, swim, and participate in other activities while wearing the sensor?

You can wear the sensor while bathing, showering, swimming or exercising, but you need to be cautious. Do not submerge the sensor in water deeper than 3 feet (1 metre) for more than 30 minutes. Take care when dressing, washing, and drying the skin around the sensor to avoid accidentally peeling it off.

Is the FreeStyle Libre flash glucose monitoring system the same as a continuous glucose monitoring system (CGM)?

No, the FreeStyle Libre flash glucose monitoring system is not the same as a CGM.

CGM systems continuously display your blood sugar levels on a receiver, while flash glucose monitors only show the glucose level when you scan the sensor with a Reader.

Buy FreeStyle Libre Online from Prescription Doctor today!

You can buy the FreeStyle Libre Sensors online from Prescription Doctor's UK-based GPhC-registered pharmacy.

Our doctors are on hand to ensure the device is safe for you. All items available from our online private pharmacy service are approved by the MHRA and are dispatched from our brick-and-mortar pharmacy via a next-day, discreet delivery service to ensure your confidentiality.