Expired Diabetic Test Strips: Should you use them?
One of the biggest debates concerning diabetic test strips has always centered on the use of test strips beyond the expiration date. The reason for such a big swing on both sides is the fact that an expired box of test strips may read very close to a test strip that hasn’t expired (within 5 points on either side). This then leads the patient to believe that all expired test strips are fine to use as long as the strips aren’t ‘too old’.
After combing several blogs, I’ve noticed that a large number of diabetic patients who use expired test strips believe the Pharmaceutical industry places an expiration date on test strips in order to generate a larger, more steady income. On the other hand, the patients who believe test strips expire seem to all have stories about getting incorrect readings when testing against newer dated test strips.
So, is it true that the Pharmacy industry is setting expiration dates for their own personal gain? To find the correct answer, we must first understand what a test strip is actually made of in order to determine if an expiration date is really needed or not.
What’s inside a Diabetic Test Strip?
A Diabetic test strip, like the Nipro TRUEtest Glucose test strips, consists of a coating on the top layer in order to protect and seal the components and circuit of the strip. The sample chamber is the window in which your blood sample is initially placed on. The chamber has several different parts attached including the spacer, two adhesives that fit in between the spacer, and a liquid attracting layer. All of these parts combined assist in moving the blood sample to the strip known as the chemistry strip.
The chemistry strip has two major components. The first is the enzyme which is a ‘living’ protein that attaches itself to glucose in the blood sample that in turn, pulls off several sugar electrons. The second make-up of the chemistry strip is the mediator which passes the enzyme through the circuit which induces heat by quickly passing them off to the strips circuit.
It’s amazing that so much is packed inside of a single test strip! After dissecting the different components that make up one tiny strip, it seems clear as to why there is an expiration date set for test strips. The fact that there is a living enzyme within a strip sheds light as to why, after the expiration date, that some patients will get good readings while some may not. The expiration date is set to a date that is well within the time period of the life of the specific enzyme. Once the date passes, the enzyme may stay intact for a while longer, but, sooner or later it will break down.
To diabetic patients, it’s important to get the best possible reading the first time around and for this reason alone, I would say to waiver against using expired test strips.