What the barcode on an eye drop box means

The barcode on an eye drop box is usually a UPC, a 12-digit number that GS1 US calls a GTIN-12. It identifies the product itself, the same on every box of that item, so a register or website can look it up. It doesn’t hold the price, the lot number or the expiration date. Quell’s carton UPC is 860008931115.

What does a UPC code tell you?

GS1 US, the organization that issues barcode numbers to companies in the United States, describes a GTIN (Global Trade Item Number) as an identification key used to identify a trade item. It also says a UPC is synonymous with a GTIN-12, and a GTIN-12 is always 12 digits. In plain terms, the number says “this exact product, from this company, in this size.”

What the number doesn’t carry is just as useful to know:

• It doesn’t contain a price. A store’s system looks up its own price when the code is scanned.
• It doesn’t identify the batch. Every Quell carton has the same UPC, whichever lot it came from.
• It doesn’t contain an expiration date.
• It isn’t a safety or quality mark, and it doesn’t mean a product was reviewed by anyone.

What do the numbers on a UPC code mean?

According to GS1 US, the 12 digits of a GTIN-12 break into three parts:

• A company prefix, assigned by GS1 to the brand owner.
• An item reference, which the company assigns to each product. GS1 notes that this part carries no built-in meaning; it’s simply a unique number.
• A check digit at the end, calculated from the other 11.

The company prefix and item reference together always total 11 digits, but the split between them varies by company, so you can’t tell where one ends and the other begins just by looking.

The check digit, using Quell as an example

The last digit exists to catch mistakes, such as a misread scan or a typo when someone enters the number by hand. Quell’s UPC is 860008931115, and its check digit is the final 5. Here’s how it works out:

• Add the digits in the 1st, 3rd, 5th, 7th, 9th and 11th positions: 8 + 0 + 0 + 9 + 1 + 1 = 19.
• Multiply that by 3: 57.
• Add the digits in the 2nd, 4th, 6th, 8th and 10th positions: 6 + 0 + 8 + 3 + 1 = 18.
• Add the two results: 57 + 18 = 75.
• The check digit is whatever brings that total up to the next multiple of 10. From 75, that’s 5.

If a single digit were mistyped, the math would almost always fail, and the scanner or system would reject the number. GS1 US offers a check digit calculator on its site for anyone who wants to try it.

Barcode vs. NDC number

The NDC, or National Drug Code, is a separate identifier for drugs in the United States, used in FDA listings. It’s a different system from the GS1 barcode, even though on some medicine boxes the two share digits. This site doesn’t publish an NDC for Quell, and the barcode number shouldn’t be read as one. Our guide to the NDC number on eye drops explains how that code is structured and where to find it.

Barcode vs. lot number and expiration date

The lot number identifies the specific production batch, and it changes from run to run. The expiration date tells you how long that batch is good for. Both are usually printed or stamped separately from the barcode, often on a flap, the bottom of the carton or the bottle label. If you ever need to report a problem with a bottle, the lot number is the code a company asks for, not the UPC. See what the lot number on eye drops means.

• UPC: same on every box of the product.
• Lot number: same within one batch, different between batches.
• Expiration date: tied to the lot.
• NDC: a drug listing code, separate from all three.

Where you’ll see Quell’s UPC

The UPC is printed with its bars on the carton. The same 860008931115 is the number online listings use to match the product; this site provides it in the product information it gives to search engines and shopping listings, so the item can be recognized as one product wherever it appears.

Knowing the number helps if you’re checking that a listing elsewhere refers to the same .33 fl oz (10 mL) Quell carton. It doesn’t, on its own, prove a box is genuine, since anyone can print a barcode. If you have doubts about a package, our guide on how to tell if eye drops are counterfeit covers what to check, and buying from quelldrop.com means it ships directly from Brentwood, Tennessee.

Scanning a barcode with your phone

Barcode apps look up the number in whatever database they use. Results can be incomplete, out of date or wrong, especially for smaller brands. Take what an app shows as a hint, not as the label. The label on the carton and the Drug Facts page are the source for what Quell contains and how to use it.

What the barcode can’t tell you about using the drops

Nothing about directions, warnings or ingredients lives in the barcode. For that, read the Drug Facts panel. Quell’s Uses read: For use as a protectant against further irritation or to relieve dryness of the eye. Its directions read: Apply 1 drop 3 times per day in each eye. One caution appears under Warnings: Caution should be used in those with egg or bird allergies — For use in the eyes only. And if something about a bottle looks wrong, such as a broken seal or a leak, contact us at 615.465.6041, M–F 9AM–5PM CST.