
The Freestyle Libre 3 is a game-changer in CGM, allowing users to get glucose readings in real-time without traditional fingerstick testing. However, some users have reported Freestyle Libre 3 false low readings at night. If this is happening to you, it can be pretty scary, mainly when you’re relying on the device to help you manage your diabetes. This blog will describe why these erroneous readings may occur, their effect, and how to deal with them.
What is the Freestyle Libre 3?
The Freestyle Libre 3 is a game-changing device in diabetes care. A small sensor worn on the skin continuously tracks glucose levels through interstitial fluid, the fluid between cells. The sensor wirelessly communicates with a smartphone or reader to provide real-time glucose readings. Unlike conventional blood glucose meters, the Freestyle Libre system eliminates the need for frequent fingerstick tests, making it popular among people with diabetes.
Though convenient, no device is without potential issues, and some users have reported inaccuracies in the form of false low readings, especially at night.
What are False Low Readings?
A false low reading occurs when the glucose level read on the Freestyle Libre 3 is less than the blood glucose level. For instance, if your sensor reads 50 mg/dL, but a fingerstick test confirmed that your blood glucose was 100 mg/dL, that would be considered a false low.
The person might be in danger if their decision to make an insulin dose adjustment or even judgment regarding their health condition is taken solely based on CGM. It is specifically dangerous at night because the patient might not wake up to watch for or rectify the errors.
Causes of Freestyle Libre 3 false low readings at night
Several factors can be considered responsible for Freestyle Libre 3 false low readings at night:
1. Sensor calibration and interference:
Unlike other types of CGMs, Freestyle Libre 3 does not depend on manual calibrations, but there might be cases wherein environmental interference and sensor malfunctions may sometimes skew the results. For example:
- Sensor position: Placing the sensor in areas with relatively poor circulation and muscle tissues, like the upper arms, can result in an unreliable reading, especially at night, and blood flow may be less vigorous.
- Pressure: Laying on the sensor at night compresses the device and makes it read something lower than is present.
2. Presence of Other Elements:
- Hydration levels: The CGM measures glucose in the fluid between cells’ interstitial fluid, while hydration levels and dehydration are not constant. Often, dehydration conditions are more nocturnal, so the sensor may display its readings falsely on the lower levels.
- Temperature changes: The sensor is sensitive to temperature changes. Body temperature changes may occur when one is asleep, especially if under the blankets or in case of temperature changes in the room. Such high temperatures may distort the sensor readings.
3. Response Delay of CGM
- As with all CGMs, the Freestyle Libre 3 does not measure blood glucose. Instead, it takes readings in the interstitial fluid. These are typically 10-15 minutes behind the glucose in the blood, especially in rapidly changing blood glucose. These effects can become very apparent at night since the body tends to have many fluctuations in its glucose levels based on basal insulin effects or digestion.
- This means that, in case of rapidly increasing or falling blood glucose levels at night, the readings might be stale or even inappropriate.
4. Insulin action at night:
- Even when you do not eat, and you are under long-acting insulin, or you have an insulin pump, its action can push glucose levels downwards without warning in the night hours. This can lead to false lows at times, where the sensor will interpret the low slope of decreasing glucose.
5. Device flaw or malfunction
• An incorrect reading is infrequently caused by a sensor or reader malfunction. This might be due to manufacturing defects, software problems, or physical damage to the sensor.
Effects of False Low Readings
Freestyle Libre 3 false low readings at night False low readings have a significant effect on diabetes management:
1. Treatments Administered Unnecessarily:
You may do things you wouldn’t otherwise do because you feel that you’re hypoglycemic, based on the erroneous reading: consume sugar or alter your insulin, for example. This could create a rebound in high glucose levels several hours later, which may wake you up at night and interfere with glucose control.
2. Sleep Disturbance
Diabetes patients at night are particularly vulnerable to hypoglycemia attacks, especially on days or nights when taking insulin. An action based on a false reading of lowness may make one wake up during the night to grab a snack or adjust the insulin level, leading to a broken night’s sleep and groggy or fatigued the following day.
3. Lower Confidence in CGM:
Persistent false readings undermine one’s confidence in the device, making it difficult to rely on it for accurate readings. This results in reverting to old ways—the fingerstick test, which tends to be time-consuming and somewhat inconvenient.
Handling False Low Reading
If false low readings of your Freestyle Libre 3 are occurring nocturnally, here is how to handle it –
1. Verify a Fingerstick Test:
If the reading returns a questionable low reading, always confirm it with a fingerstick test. It is far better to double-check the data than to base your decision on incorrect data.
2. Sensor Sites Change:
Change sensor sites to determine the location with the most accurate reading. The abdomen, upper arm, or back of the arm are generally preferred as they have better circulation and a more consistent reading.
3. Avoid Pressure on Sensor:
Take care of where and how you sleep so it does not hit your sensor or interrupt the reading.
4. Hydrate Well:
Staying hydrated during the day and at night will help the sensor work better. If someone is dehydrated, fluid levels in the interstitial space can change, causing glucose levels to not accurately reflect with the sensor.
5. Use the Freestyle Libre 3 App for Trend Analysis:
Use either the Freestyle Libre 3 app or the reader to find the long trend of your glucose data. Sometimes, you can learn the pattern of why the value is low, whether it genuinely is an aberration or an example of some more significant trend.
6. Discuss with your Healthcare Provider
If you continue to experience false low readings, consult your healthcare provider or diabetes care team. They may be able to adjust your insulin regimen or help troubleshoot the device.
Conclusion
The Freestyle Libre 3 is a vital tool in diabetes management, yet like all technology, it has imperfections. Freestyle libre 3 false low readings at night can sometimes annoy some, but understanding their causes can sometimes have an impact. Confirming your readings with a fingerstick test, adjusting your sensor placement, staying hydrated, and monitoring your trends will allow you to know that the device is there for you as a reliable and accurate companion in glucose management.
If these issues persist, do not hesitate to discuss possible solutions with your healthcare provider. With the right approach, you can continue to benefit from the convenience and accuracy that the Freestyle Libre 3 offers.