Is It Safe To Use Expired Glucose Test Strips

How Do Glucose Tests Work?

Your test strips may appear to be nothing more than a piece of plastic at first glance. However, they are a little more complicated and important. The layers that make up glucose test strips all serve a distinct purpose in presenting your test results.

The enzyme glucose oxidase is in each test strip and reacts to the levels of sugar in your blood. Thus, resulting in the production of gluconic acid from the glucose in the blood. The meter sends a current to the test strip from the opposite end. The test strip has electric terminals that the meter may use to detect the current flowing between them.

The amount of gluconic acid generated affects the current between the terminals. The blood glucose meter then calculates the blood glucose level using an algorithm based on the current differential. If more blood is needed during the test, certain blood glucose test strips allow you to reapply it to the same strip. A test strip’s blood requirement varies depending on the manufacturer. 

Why Do Test Strips Expire? 

Glucose test strips have a shelf life because of the enzyme on each strip. Each strip’s glucose oxidase enzyme has a limited lifespan and will eventually “die.” This is because the enzyme begins to degrade. The longevity of the enzyme on each of your diabetic test strips is determined by the expiration date on the box.

However, the expiration date isn’t always accurate. For example, just because the strips expire on February 18th reveals nothing about how effective they are on February 17th and 19th. In general, if your test strips haven’t expired in the last week, you can usually use them with some accuracy. Strips that are months or years past their expiration date are not the same.

Each brand has a unique enzyme “tolerance,” which means that the enzyme will break down faster or slower than other brands. This determines how long you can use a test strip after it has expired while still getting reasonably accurate results. When you open the box of test strips and expose them to oxygen, these enzymes begin to break down. 

If the bottle of diabetic test strips has sat unopened in a manufacturer-recommended storage setting, the strips may be useful for up to a year after the expiration date.

Should You Use Expired Glucose Test Strips?

There isn’t a perfect option for whether or not you should use expired strips, but in general, you shouldn’t. But why? Hundreds of small studies conducted by private individuals have resulted in a plethora of anecdotal evidence. For example, one person has no luck with test strips that are only a few days past expirations, whereas another has no luck with test strips that are 6 months past expiration with the same level of accuracy. 

The question is if you are okay with taking a chance on the accuracy of your results in order to save a few dollars?

If you’re in a pinch and don’t have any additional unexpired diabetic test strips, you can use an expired test strip to get a rough estimate of your blood sugar levels. Just keep in mind that these readings are unlikely to be accurate in any manner, so avoid making any health decisions based on them.