How to Read a Lot Number on Medical and Lab Labels

General product-label information only, not medical advice. For a specific product, the manufacturer’s instructions for use and label govern.

To read a lot number, find the line on the label or box marked as lot or batch (often shown with the symbol or the letters LOT), copy it exactly as printed, then read the expiration date as a separate field. The lot number identifies a production group; it does not encode the expiry date. This guide covers medical and laboratory product labels, for people who receive, check or log supplies. It sticks to what U.S. regulations say about device labels and does not repeat the definition covered in lot number.

What you need

• The product’s immediate label and its outer box or carton, since either may carry the lot and date.
• Good light, and magnification if the print is small.
• The packing slip, order record or recall notice you plan to match the lot against.
• A way to record the lot exactly as printed (a log, a receiving form or a photo of the label).

What a lot number is, in regulatory terms

Under FDA’s device regulation 21 CFR 830.3, a lot or batch is one finished device or more that consist of a single type, model, class, size, composition or software version, are manufactured under essentially the same conditions, and are intended to have uniform characteristics and quality within specified limits. The same section defines the expiration date as the date by which the label of a device states the device must or should be used. These are two different pieces of information: the lot says which production group the item belongs to, the expiration date says when to use it by.

Steps

Where is the lot number on a medical product box?

Look on both the box and the item label for a field labelled lot, batch, or LOT. The U.S. device-label rules cited here do not fix a position on the package, so there is no universal spot: check each side of the carton and the label of the item inside. If a unique device identifier (UDI) is present, the lot appears in its production-identifier portion, which 21 CFR 830.3 describes as the variable part of a UDI that can include the lot or batch, serial number, expiration date and manufacturing date when they are on the label. See UDI for medical devices and medical device labeling symbols.

1. Find the lot or batch field. Read the characters exactly, including letters, digits and any dashes.
2. Find the expiration date field separately. It is its own printed date, not something you work out from the lot characters.
3. Read the date in its printed format. Under 21 CFR 801.18, a printed expiration date, manufacture date or other date meant for the user on a medical device label is presented as a four-digit year, two-digit month and two-digit day separated by hyphens, so January 2, 2014 appears as 2014-01-02. Exceptions in that section include combination products bearing an NDC number and certain electronic radiological products. Labels that follow another format are still read as printed; do not convert guesses.
4. Compare the plain text with the barcode. 21 CFR 801.40 requires the UDI in two forms, easily readable plain text and automatic identification and data capture (AIDC) such as a barcode; if the AIDC is not evident on visual examination, the label or package must say it is present. A production identifier segment is required when the label includes a lot or batch, serial number, manufacturing date or expiration date. For how barcode data identifiers carry a lot and a date, see the worked example in GS1-128 barcodes.
5. Record the lot as printed. Match it to the packing slip or the recall notice character by character.

How do I read lot and expiry together?

Read them as a pair of separate fields on the same label: the lot number names the production group and the expiration date gives the use-by date for that item. Record both together (for example, lot as printed plus date as 2014-01-02 style), and never infer one from the other. For reagents and test strips, see test strip expiration and reagent lot-to-lot verification.

Lot number meaning and the barcode lot number

The lot number means the item came from a defined production group under essentially the same conditions (21 CFR 830.3). A barcode lot number is the same lot, encoded for machine reading; it should agree with the human-readable line. FDA’s UDI basics page notes that the device identifier (DI) identifies the labeler and the specific version or model of a device, while the production identifier is the variable part. The FDA GUDID database does not include the production identifier, so you cannot look a lot number up there; search the DI at AccessGUDID to identify the device itself. See UDI labeling and GUDID submission.

What can go wrong

• Lot confused with another number. A catalog number, serial number or UDI is not the lot. A serial number identifies a single unit, whereas a lot covers a group.
• Letters and digits misread. A letter O and a zero, or an I and a 1, can look alike in small print; copy the label or photograph it rather than retyping from memory.
• Date format misread. A label date in year-month-day form with hyphens is different from a day-first or month-first habit; read the whole date and check which component is which.
• Box and item disagree. If the outer box and the item show different lot numbers, record both and raise it before use or receipt is accepted.
• Looking the lot up in GUDID. The production identifier is not in GUDID, so a lot search there will not return a result.

When to get professional help

Contact the manufacturer or labeler printed on the label if a lot, expiry or barcode is missing, unreadable or inconsistent, or if a recall notice lists a lot you hold. For a suspected product problem, FDA’s device reporting channels and your facility’s quality or compliance contact are the proper routes. This page does not give individual medical advice.

FAQ

Where is the lot number on a medical product box?

It is in a field marked lot, batch or LOT on the box, the item label, or both. The rules cited here do not set one position, so check every side of the carton and the item label.

How do I read lot and expiry together?

Treat them as two separate printed fields. Copy the lot exactly as printed, read the expiration date in its printed format (U.S. device labels use year-month-day with hyphens, as in 2014-01-02), and record both together.

Can I tell the expiration date from the lot number?

No. The lot identifies a production group and the expiration date is its own printed field (21 CFR 830.3).

Can I look up a lot number in FDA’s GUDID?

No. GUDID does not include the production identifier, which is where the lot sits. Search the device identifier instead.

Sources

• 21 CFR 830.3, definitions (lot or batch, expiration date, production identifier): ecfr.gov, checked 2026-10-30.
• 21 CFR 801.18, format of dates on device labels: ecfr.gov, checked 2026-10-30.
• 21 CFR 801.40, UDI form and content: ecfr.gov, checked 2026-10-30.
• FDA, UDI basics: fda.gov, checked 2026-10-30.