Regular monitoring of blood glucose levels is an essential part of good diabetes care. Keeping an eye on your blood sugar levels helps you make decisions, in collaboration with your healthcare team, about nutrition, physical activities and when to take your medications. These are all important decisions that can delay or prevent diabetes complications such as heart attack, blindness, and amputation.
In previous blogs we covered various methods to monitor glucose levels, including continuous glucose monitoring devices but also emerging technologies like using saliva as a pain-free and cheaper alternative to blood for monitoring diabetes, measuring glucose in your tears and using a smart-patch.
Diabetes test strips for blood glucose monitoring
One of the more common ways of monitoring blood glucose levels is using diabetes test strips. These are small disposable strips made of plastic that pack a lot of technology into a small space. They may look insignificant but play in fact a crucial role in good diabetes care for millions around the world.
But how does it work in practice? First, you put a test strip into your blood glucose meter and prick your fingertip with the meter’s tiny needle, which is called a lancet. Then, you squeeze out a droplet of blood and place it onto the glucose strip. Below you can see an instructional video on how to test your blood glucose.
The test strips are coated with a thin layer of gold that is cut into a pattern, which becomes the strip’s circuit. On one end of the strip, there’s a chemical called glucose oxidase that produces gluconic acid from the glucose in the blood. So, when blood is placed onto the test strip, it soaks up your blood like a sponge, reacts with the chemical and turns the glucose into electricity.
At the other end of the test strip, the meter transfers a current to the test strip, which has electric terminals that allow the meter to measure the blood glucose levels. A number appears on the meter that reflects the speed of the electric current – the more blood sugar is detected the stronger the signal, which means a higher number on your blood glucose meter.
How long does a diabetes test strip last?
What about the lifespan of these blood glucose test strips? For years, it has been debated whether people with diabetes can safely use expired test strips. Some claim that the test strips can be used for a short period of time beyond their expiration date if the test strips have been stored properly and any damage to the strips has been avoided. However, this could lead to an inaccurate reading of the blood glucose.
Can expired test strips give false reading?
The US Food and Drug Administration (FDA) even specifically warns against using expired diabetes test strips as they might lead to inaccurate results. Most experts maintain that the test strips should be used before the expiration date, which should be found on the strips or the box, in which they arrived. After opening, blood glucose test strips can normally be used for three to six months but for this it’s important to refer to the information provided for each brand of test strips.
Accuracy is key when testing your blood sugar. Before considering using expired test strips, it is vital to ask yourself a few questions about their potential effectiveness. This inncludes how they have been stored, or have they been exposed to dampness or high humidity levels. It is also crucial to take into account how long after the expiration date they can be safely used, and which are the potential risks of using expired test strips.
While it may be tempting for some to use expired test strips, there’s great need for caution and it’s important not to underestimate safety concerns. It’s clear that the active ingredients found on the test strips will not last forever. Patients who decide to use expired test strips must assume the risk of inaccurate results, which can have a detrimental impact on their health. Staying on the safe side by only using test strips that have not expired seems to be the best option for good diabetes care and optimal health outcomes.