If you're deciding what to do with extra test strips, the most important thing you can do takes ten seconds: find the printed expiration date on each box. That single number determines whether your strips can be used, donated, or sold — and how much they're worth. It's worth understanding why it carries so much weight.
Why test strips expire at all
A test strip isn't an inert piece of plastic. Each one is coated with glucose-reactive enzymes that react with a drop of blood to produce a reading. Like most chemistry, those enzymes degrade over time — accelerated by exposure to air, heat, and humidity. As they break down, the strip's readings drift off from the truth. Manufacturers set the expiration date using accelerated aging studies that identify the point where accuracy can no longer be guaranteed.
Why accuracy is not negotiable
This isn't fussiness. An inaccurate reading from a degraded strip can hide a dangerous high or low — the kind that leads to real emergencies. That's why both the people using strips and the programs that redistribute them insist on unexpired, well-dated boxes. Safety is the whole point.
Why dating drives resale value
Because accuracy depends on freshness, the expiration date is the biggest lever on what a box is worth. Think of it from the buyer's side: strips are only useful if they reach someone who can test with them *before* they expire. A box dated two years out has a long runway. A box with three months left is nearly out of road.
- Long dating (a year or more): the most valuable — plenty of useful life left.
- Medium dating (roughly 6–12 months): still solid and readily sellable.
- Short dating (a few months): reduced value, and some donation programs won't accept it — but usually still better to sell than to let it expire.
- Expired: not usable, not sellable, not donatable. This is the outcome to avoid.
Most buyers, including us, look for boxes with a comfortable margin — typically at least six months before the printed date. It's the same reason we tell people not to wait: every month that passes lowers the value of what's sitting in the drawer.
How to store strips so they last
Good storage protects both the strips' accuracy and their resale value. The rules are simple:
- Keep them sealed. Leave boxes and vials unopened until use — the seal is what protects the enzymes. An opened box can't be sold or donated anyway.
- Room temperature, roughly 68–77°F. Avoid extremes.
- Away from humidity. Not the bathroom, not a steamy kitchen counter. Moisture is the enemy.
- No car glove boxes, no windowsills. Heat and direct sun degrade strips fast.
- Don't freeze them. Cold extremes are as damaging as heat.
Store them like they still matter — because to your wallet, and to the next person, they do.
The takeaway
Check the date, store them sealed and cool, and act while the dating is long. If you've got boxes with good time left, that's precisely when they're worth the most — so it's the best moment to get an offer rather than let another few months tick by.
Got sealed boxes to turn into cash?
Tell us the brand, quantity, and expiration dates. We'll send a no-obligation cash offer and set up a local meetup across the Salt Lake Valley.