How to Find the REF, LOT and Expiration Date
We buy sealed diabetic supplies for cash. We do not sell supplies.
You'll find the REF, LOT and expiration date on the printed label on the outside of the box. Each one sits next to a small symbol. REF is the product number, LOT is the batch, and the date next to the hourglass is the use-by date.
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This page is general information, not medical or legal advice. Talk to your doctor or pharmacist about your own care.
These symbols are used on medical devices around the world. Once you know them, you can read almost any supply box in a few seconds.
What do the label symbols mean?
The symbols come from ISO 15223-1, a standard for medical device labels. The FDA lets makers use these standard symbols on labels without words next to them.
Here's what the common ones mean:
| Symbol | What it means |
|---|---|
| REF in a box | Catalog or reference number for the exact product |
| LOT in a box | The batch the product was made in |
| SN in a box | Serial number for that one item |
| Hourglass | Use-by date |
| Factory | Date the product was made |
| Thermometer | Storage temperature range |
The factory symbol trips people up. That date is when it was made, not when it expires. Always look for the hourglass.
Finding the REF, LOT and expiration date
The label spot changes by brand. Here's where to look:
- Dexcom G7 and Stelo. Check the label on the outside of the sensor box. The G7 15 Day box also says "15 Day" on the front.
- FreeStyle Libre. The FDA says the serial number is on the label on the bottom of the applicator or carton.
- Omnipod. Check the label on the pod box. Sensor logos sit in the upper right corner.
- Test strips. Check both the box and the vial. The dates should match.
Not sure which Dexcom box you have? Our guide on G7 15 Day vs 10 Day shows where to look.
How do you read the date?
Dates are often printed year first, like 2027-03-31. That means March 31, 2027.
Some labels show only a year and month, like 2027-03. If you're not sure how to read a short date, check the maker's insert or ask your pharmacist.
Look closely at the order of the numbers. A date like 2027-03-04 is March 4, not April 3. Reading it wrong can make you think you have a month more, or less, than you do.
Don't use supplies past the hourglass date. The FDA warns that expired test strips may give incorrect results. Our guide on reading expiration dates goes deeper.
Which date counts, box or item?
Each sealed item inside usually has its own label too. But you shouldn't open a sealed box just to check.
If you're selling, go by the outer label. If two boxes have different dates, photograph each one. A buyer needs the date for every box, not just one.
If you're using the supplies, check each item's date when you open it. Use the oldest dates first.
A simple trick helps. When a new box comes, write the hourglass date on the front in big numbers with a marker. Don't cover the label. Now you can see every date from across the room.
Why do the REF and LOT matter?
The REF tells you exactly which product and version you have. Two boxes can look the same and still have different REF numbers.
The LOT matters for recalls. Makers and the FDA often name affected lots or serial numbers. For example, Abbott set up FreeStyleCheck.com so you can check a Libre sensor by its serial number.
When a recall happens, you'll want those numbers handy. A photo of each label on your phone makes that easy.
The REF also helps when you call the maker. Customer care can look up your product fast if you read them the REF and LOT. It saves you from describing the box in your own words.
Keep the box, even after you use the item inside. If something goes wrong with a sensor, the maker may ask for the LOT. The outer box is where it's printed most clearly.
A real-life example
Say you're cleaning out a closet and find a dozen supply boxes. Some are sensors, some are pods and some are strips. You don't know which are still good.
Take one box at a time. Find the hourglass, then write down the product name, the REF and the date. Snap a photo of each label as you go.
Make three piles as you work: good, expired and not sure. The "not sure" pile is for boxes with worn or hard-to-read labels. You can ask the maker about those later.
In about 20 minutes, you have a full list. You know what's good, what's expired and what to check for recalls. You also have everything a buyer would ask for.
What photo should you send a buyer?
Take three photos for each kind of item:
- The front of the box, with the product name in view.
- A sharp close-up of the label, with REF, LOT and the hourglass date in focus.
- One group photo with your total count.
Use daylight and hold the phone steady. Tap the screen on the label so your phone focuses there. If there's a glare, tilt the box a little.
Leave the pharmacy sticker on, even if it covers part of the label. You can black out your name with a marker. We remove and shred pharmacy stickers ourselves.
Keep reading
Questions
What does REF mean on a medical box?
REF is the catalog or reference number. It tells you the exact product and version.
What does LOT mean?
LOT is the batch number. Makers use it to track products, and recalls often name specific lots.
Which symbol is the expiration date?
The hourglass. The date next to it is the use-by date, often written year first.
Is the factory symbol the expiration date?
No. The factory symbol shows when the item was made. Look for the hourglass instead.
Found sealed supplies you can't use?
Once you have the REF, LOT and expiration date, you have what a buyer needs. We buy sealed, unexpired CGM sensors, Omnipod pods and test strips, and we never charge a fee. Send a photo of the label for a free quote.