Glossary: Lot and Batch

Batch — a quantity of material produced together under the same conditions, in a single production run.

Lot — an identified quantity of product treated as a unit for tracking purposes. A lot may correspond to a batch, be a subdivision of one, or be assembled from more than one.

They are used interchangeably in conversation. They are not the same thing, and the difference is where certificates of analysis stop resolving.

Why the distinction matters

25 TAC §300.301(d) requires sample and lot identification among the twelve fields on a certificate of analysis.

That field is what connects the document to a physical thing. Without a resolvable identifier, a certificate describes an abstraction — it may report that some material tested a particular way, without establishing that the jar on your shelf is that material.

Where it breaks

The failure is almost never fraud. It is ordinary friction:

• a laboratory reports a sample ID that maps to a batch, while your inventory tracks lots
• a supplier records the identifier one way on the invoice and another way on the label
• a case is repacked or relabelled, correctly and helpfully, severing the link
• two deliveries of the same product arrive close together and are shelved as one

Each is unremarkable. Each breaks the join between the paper and the product.

The rule for handling a mismatch

Do not resolve it by inference.

Same supplier and same week is not the same lot. A probabilistic match recorded as a fact produces confident evidence with nothing behind it — which, in an evidence system, is worse than recording no answer, because no answer prompts someone to go and look.

Record the disagreement as a visible open state: these two records are supposed to describe the same thing, here is exactly how they differ, and a person decides.

Related terms

Sample identification — the laboratory's identifier for the material it tested. Related to, and frequently not identical with, your lot identifier.

Evidence chain — product, lot or batch, and laboratory record all describing the same thing. The chain is exactly as strong as the weakest of those links.