Source of Batch number

{{Infobox concept | name = Batch number | subtitle = Identification | Also called = Lot number, lot code | Assigned at = Production, or at fill, or at packing | Function = Links container to production and testing records }} A '''batch number''' — equivalently a lot number — is the identifier assigned to a quantity of material produced under uniform conditions. It appears on the container label and on the [[Certificate of analysis|certificate of analysis]], and it is the only thing connecting the two.{{r|iso9001}} The number itself carries no information about quality. Its function is referential: it allows a determination recorded against a lot to be applied to a container, and it allows a container to be traced to production records. A batch number with no records behind it is a string of characters.{{r|usp1503}} What can be observed about a batch number is whether it is present, whether it is consistent across the vial, the certificate and the shipping paperwork, and whether the supplier can retrieve records against it after the fact. See [[Lot traceability]]. == Assignment == Numbers may be assigned at several stages, and the stage determines what the number identifies. A number assigned at synthesis identifies a production campaign; at purification, a pool; at fill, a filling run; at packing, a shipment. These are not equivalent, and the same physical material can carry different identifiers under different schemes.{{r|ich_q7}} Formats vary and no convention is universal. Common patterns encode a date, a product code and a sequence; others are opaque serial numbers. An encoded date is convenient but is not verification: a date embedded in an identifier is an assertion like any other field on a label. The practical consequence is that comparing batch numbers between suppliers, or inferring production volume from sequence numbers, is unsound. Sequence numbers may be per-product, per-year, per-line or arbitrary. == Consistency checks == A purchaser can check a small number of things without any laboratory work. * The identifier on the vial matches the identifier on the certificate. * The identifier appears on the invoice or packing list. * Where a consignment contains several units, they either share an identifier or the paperwork accounts for more than one. * Dates on the certificate are ordered sensibly: manufacture before testing, testing before release, release before any retest date. Failure of any of these is a documentary observation. It says the paperwork does not hang together; it does not say the material is defective, and conflating the two is a frequent error in community discussion.{{r|reports}} The check most often omitted is the last. A certificate whose retest date precedes its release date, or whose test date precedes its manufacture date, is defective on its face and can be identified without expertise. == What a batch number cannot do == A batch number does not establish that the lot exists as described, that the certificate is genuine — see [[Test report forgery]] — or that the vial was filled from that lot. It is a pointer, and a pointer is only as good as what it points to.{{r|usp1503}} It also does not survive [[Repackaging|repackaging]] unless the repackager records the original identifier. A vial relabelled with a new identifier and no back-reference has been disconnected from every determination ever made on the material it contains. For material bought outside licensed supply, the batch number is nonetheless the most useful single field on a label, because it is the field against which everything else can be checked for consistency. Its absence removes the possibility of any documentary check at all.{{r|reports}} == References == {{reflist}} <ref name="iso9001">ISO 9001:2015, ''Quality management systems — Requirements'', clause 8.5.2.</ref> <ref name="usp1503">United States Pharmacopeia, General Chapter <1503>, ''Quality Attributes of Synthetic Peptide Drug Substances''.</ref> <ref name="ich_q7">International Council for Harmonisation, ''Q7: Good Manufacturing Practice Guide for Active Pharmaceutical Ingredients'' (2000).</ref> <ref name="reports">PeptidePedia Wiki community test-report tally, 2024–2026 (self-reported; see [[Project:Sourcing_guidelines]]).</ref> == See also == * [[Lot traceability]] * [[Certificate of analysis]] * [[Repackaging]] * [[Test report forgery]] * [[Chain of custody]] {{DEFAULTSORT:Batch number}} [[Category:Traceability]] [[Category:Certificates of analysis]] [[Category:Quality and testing]]