People with diabetes are probably familiar with the handy little strips they use to test their blood glucose levels. However, do you pay attention to their expiration dates and should you use expired strips?
First, we must know the material they are made of in order to understand their expiration. The strips are made of plastic but coated with the enzymes glucose dehydrogenase or glucose oxidase. They are proteins made by living organism cells which do break down over time.
The enzyme from the strip reacts with the blood’s glucose and converts it into an electrical current which enables the glucose meter to show the glucose concentration.
So, since strips have parts of living organisms, they do expire.
Factors That Affect the Expiration Date of Diabetes Test Strips
Even though there’s a scheduled expiration date on diabetes test strips, we should know the factors that affect it, which include:
- The use of different enzymes – some companies use a less stable enzyme with a better accuracy. Others use less accurate enzymes with longer-term storage. And third, might use the cheapest alternative.
- Storage – the place where we keep our diabetes test strips affects their expiration date. Keeping them at a too low or high temperature could alter their performance. Humidity and exposure to air are another factors that affect their expiration. Also, make sure they nothing damages them.
- How much time has passed since they have expired
The Accuracy of Expiration Dates
If the expiration date says the strips will last until December 1st, does it mean they will give an accurate result the day before, and a wrong one the day after?
Well, the reality is there’s no such accuracy that can tell the exact day the strips will expire. In fact, most manufacturers set the bar a bit lower than the ‘real’ expiration date. They do this to protect themselves from unsatisfied and even harmed users.
Nevertheless, many tests on different diabetes test strips showed that there isn’t a big difference in the blood glucose reading when using a current or an expired strip.
Still, the results will depend on the brand, storage, as well as how long the strip was expired.
So, a strip expired for few days or months shouldn’t give the same results as one expired for few years.
Should We Use Expired Test Strips as a Last Resort?
The bottom line is we never know if an expired strip will give us a right or wrong result. And, a wrong glucose reading can lead people to make a bad decision which in some cases can have serious, life-threatening consequences.
Even though our test strips could have been stored properly and made out of high accurate enzymes, we can’t really know if they will give us an accurate reading.
Some experts say it’s fine to use them for a small period beyond their expiration date, but we must expect a possible inaccurate reading.
Still, we don’t recommend you to use expired diabetes test strips. On the contrary, using current strips will give you accurate blood glucose reading, thus contributing to a proper diabetes management.