A batch or lot number is a way to distinguish one defined production grouping from another within the issuer's record system. It can look like an arbitrary string, but its value comes from the records it connects. The code itself is not a purity result, an expiry date or proof that the linked records are correct.
Batch and lot refer to a defined grouping
ICH Q7 uses batch and lot together in its glossary and defines the identifying number as a unique combination linked to production and distribution history. That is a useful terminology reference. It does not establish that any particular research reagent was manufactured as a GMP active pharmaceutical ingredient.ICH Q7 — Good manufacturing practice guide for active pharmaceutical ingredients (opens in a new tab)
For everyday reading, distinguish the grouping from its identifier. The batch is the material grouping; the lot code is the reference used to find its records. A code is useful because the organisation maintains that relationship, not because the letters themselves contain all the information.
Several identifiers can appear on the same document
| Identifier | Typical role |
|---|---|
| Catalogue or product code | Identifies a listed item or variant. |
| Batch or lot code | Identifies the stated material grouping. |
| Order number | Identifies a commercial order. |
| Laboratory sample code | Identifies material within the laboratory's sample system. |
| Report number | Identifies an analytical document. |
| Report revision | Distinguishes versions of that document. |
These fields may be related without being identical. For example, a laboratory can assign its own sample code while also recording the supplier's lot. A different report number therefore does not, by itself, mean a different production batch.
Copy each value under its original field name. A spreadsheet column simply called “ID” makes it easy to substitute an order number for a lot code later. Separate columns preserve the meaning and make matching records easier.
Do not infer dates from a plausible pattern
A code containing 2406 might look like a date, a sequence or an internal project number. Without the issuer's convention, none of those readings is established. Preserve it as text rather than letting a spreadsheet convert it into a date or remove leading zeroes.
ICH's Q7 questions and answers explicitly says its batch numbering requirement does not demand sequential numbers. This reinforces a practical point: a larger-looking code is not necessarily a later batch, and gaps in numbering do not establish missing material.ICH Q7 questions and answers — EMA publication (opens in a new tab)
Record the organisation and material with the code
A short identifier may be unique within one issuer's system without being unique across every laboratory and supplier. Store the issuer and product identity alongside it. Two unrelated organisations could use similar-looking strings for different materials.
A record such as “supplier S, item P, lot L” is more useful than “L” alone. If the laboratory uses sample code M, add M as a separate linked field. Do not overwrite the supplier's lot merely to make the record look simpler.
If a document changes, keep its revision information distinct from the lot. A corrected report can concern the same material. Conversely, a new lot should not inherit an older result solely because the report layout and product name are unchanged.
Use the code as the start of a traceable question
The useful next step is to connect the code to the appropriate specification and analytical document. That is a matching task, not a conclusion about quality. If the identifiers do not connect clearly, ask for the relationship to be documented before relying on the results.
Sources and further detail
- ICH Q7 — Good manufacturing practice guide for active pharmaceutical ingredients (opens in a new tab)
Section 20 definitions of batch/lot and batch/lot number. Terminology reference, not a statement that research reagents are GMP APIs.
- ICH Q7 questions and answers — EMA publication (opens in a new tab)
Question 6.2: a unique batch identifier need not be sequential.
Sources checked 19 September 2026. Worked examples are illustrative unless a supplied report is explicitly identified. This article has not undergone independent scientific peer review.