Batch Numbers and Traceability: Linking a Vial to Its Certificate

In plain English

A batch is one production run of a material, made under the same conditions and expected to be uniform throughout. It gets a code, the batch number or lot number. The two terms mean the same thing ^[1].

That number is the thread that ties everything together. It appears on the label. It appears on the production paperwork (the batch record). It appears on the laboratory report, the certificate of analysis (COA). It is also written into the shipping records, so a faulty batch can be found and called back (a recall) ^{[1, 2]}.

For a researcher, the practical point is simple. A COA describes one batch. If the batch number on the certificate does not match the number on the vial, the certificate says nothing reliable about that vial.

The short version

• Batch and lot number mean the same thing ^[1].
• One number links the label, records, certificate and samples ^{[1, 2]}.
• Retained samples let a batch be re-tested later ^{[1, 3]}.
• Distribution records make recalls possible ^{[2, 6]}.

What is a batch number?

ICH Q7, the international GMP guide for active pharmaceutical ingredients, defines a batch (or lot) as a specific quantity of material produced in a process or series of processes so that it is expected to be homogeneous within specified limits. In continuous production, a batch can be a defined fraction of output, set by a fixed quantity or a fixed time interval ^[1].

A batch number (or lot number) is a unique combination of numbers, letters or symbols that identifies a batch and from which its production and distribution history can be determined ^[1]. The guide does not prescribe a format. Manufacturers choose their own schemes, often combining a product code, a date element and a sequence number. What matters is that the number is unique and is never reused.

Why “homogeneous” matters. A single test result can stand for a whole batch only because the batch is expected to be uniform. That is why ICH Q7 asks for samples that are representative of the batch they are taken from ^[1].

How batch numbers are assigned

Several situations complicate the simple “one run, one number” picture:

• Continuous production. ICH Q7 allows the product code together with the date and time to serve as the unique identifier until the final number is allocated ^[1].
• Split and pooled batches. In solid-phase peptide synthesis, batches may be split, or sub-batches made by repeating the same steps may be combined, for example to suit equipment capacity. European guidance on synthetic peptides asks for a justification of such splitting or pooling and expects material traceability from the synthesis steps through to the final active substance ^[4]. See How Peptides Are Made.
• Blends. When batches are blended, the batch record of the blending process should allow traceability back to the individual batches that make up the blend ^[1].
• Filling and packaging. One bulk batch may be filled into vials in more than one packaging operation. The PIC/S guidance on samples asks for at least one retention sample from each separate packaging operation ^[3], so each operation remains identifiable.
• Raw materials. Each incoming material is given its own batch number on receipt, and the batch record lists the batch numbers of every raw material and intermediate used ^{[1, 2]}.

What a batch record holds

The batch record is the production history of one batch. ICH Q7 calls it the batch production and control record. It should be numbered with a unique batch or identification number, dated and signed when issued, and checked to confirm it is a correct copy of the current master instructions ^[1].

Under ICH Q7, the record of each significant step should include ^[1]:

The PIC/S Guide, which the TGA applies to Australian medicine manufacture, sets out a similar list for its batch processing record, starting with the name and batch number of the product ^[2]. Records should be kept for at least one year after the batch’s expiry date; for materials with retest dates, for at least three years after the batch is completely distributed ^[1]. How entries are made and protected is covered in Data Integrity and ALCOA+.

From batch to certificate

A certificate of analysis is the batch record’s public face. ICH Q7 says that authentic certificates should be issued for each batch on request, and should give ^[1]:

• the name of the material and, where appropriate, its grade;
• the batch number and the date of release;
• the expiry date, or the retest date, where one applies;
• each test performed, with its acceptance limits and the numerical results obtained;
• the date and the signature of authorised quality-unit staff, with the name, address and telephone number of the original manufacturer.

When someone else reissues the certificate. Repackers, agents, brokers and relabellers sometimes issue their own certificates. ICH Q7 expects these to name the laboratory that did the analysis, to refer to the original manufacturer and the original batch certificate, and to attach a copy of that original ^[1]. Distributors should also keep records that preserve complete traceability, including the original manufacturer’s identity and address, the manufacturer’s batch number, transport and receipt documents, and all authentic certificates ^[1].

This is the main way a batch number can be lost. If a material is relabelled under a new number with no recorded link to the manufacturer’s number, the chain breaks.

Retained samples: reference and retention

GMP guidance asks manufacturers to keep part of every batch. PIC/S Annex 19 distinguishes two kinds of sample ^[3]:

For finished products, the two are often identical fully packaged units and can be regarded as interchangeable ^[3]. Annex 19 also asks for records of the traceability of samples themselves ^[3].

ICH Q7 sets the rule for active ingredients: reserve samples are for future evaluation of batch quality, not for stability testing. They should be kept for one year after the batch’s expiry date or three years after distribution, whichever is longer (three years after complete distribution for materials with retest dates), in packaging equivalent to or more protective than the marketed packaging, and in enough quantity for at least two full specification analyses ^[1]. Stability monitoring is a separate programme; see Stability Testing and Shelf Life.

Matching a vial to its certificate: a worked example

The figures below are illustrative and do not describe any real product.

A good link between label and certificate shows:

1. The same batch number, character for character. “26J-0412” and “26J-412” are different numbers until a document says otherwise.
2. The same compound and labelled amount. A certificate for a 5 mg fill does not describe a 10 mg fill unless both came from the same documented batch.
3. A release date before the material was supplied, and a retest or expiry date consistent with the label ^[1].
4. Numerical results against stated limits, not only the word “Pass” ^[1]. See How to Read a Peptide COA.
5. A path back to the original. If the certificate was reissued, it should name the original manufacturer and testing laboratory and include the original certificate ^[1].

Common mismatches and what they mean

Recalls: why traceability exists

Traceability works in two directions. Backwards, from a vial to its raw materials, equipment and records. Forwards, from a batch to everyone who received it.

The PIC/S Guide states the principle plainly: records of manufacture and distribution should let the complete history of a batch be traced, and a system should be available to recall any batch from sale or supply ^[2]. Distribution records should be kept for each batch to make recall possible, and should show which batches, and how much, went to each customer ^[2]. ICH Q7 asks for a system that can readily determine where each batch was distributed, a written recall procedure, and an investigation of any failure that extends to other batches that may be affected ^[1].

In Australia, recalls of therapeutic goods follow the TGA’s Procedure for Recalls, Product Alerts and Product Corrections (PRAC), which took effect on 5 March 2025 and replaced the Uniform Recall Procedure for Therapeutic Goods. Sponsors should know, where applicable, the product name, ARTG number, batch, lot or serial numbers, and manufacture and expiry dates of the affected goods. Actions are classed by seriousness (Class I to III) and by level (wholesale, hospital, retail and consumer) ^[6]. Market actions are published in the TGA’s Database of Recalls, Product Alerts and Product Corrections (DRAC), two business days after the TGA sends its agreement letter ^[7].

How often this happens. An analysis of US FDA drug recall data from 2012 to 2023 counted an average of 330 recalls a year, each involving on average 400,000 units. The most frequent causes were impurities and contaminants (37%), followed by control issues (28%) and labelling or packaging issues (19%) ^[8]. A recall can only be limited to the affected units when batch numbers are reliable.

Serialisation. Regulators in several markets now require systems that identify products through the supply chain, adding pack-level identifiers on top of batch numbers ^[5].

Recording batch numbers in the laboratory

Traceability does not end at delivery. Guidelines on the quality control of protein and peptide reagents note that inadequate reagent quality can result in poor data reproducibility, and propose simple checks to improve it ^[9]. A review of antibody reagents describes how batch-to-batch variability, together with scarce characterisation data, makes high-quality reagents harder to choose and validate ^[10]. Recording the batch number of every reagent lets a laboratory compare results between batches and trace an unexpected result back to its source.

Batch-level checking also catches surprises. In one study, quantitative NMR found undeclared mannitol, at 20% and 43% w/w, in two custom synthetic peptides bought commercially ^[11]. The authors concluded that experimental verification supersedes trust in research quality control ^[11].

Good practice in a research laboratory:

• record the batch number, supplier, date received and certificate reference for each vial;
• keep the certificate with the laboratory record, linked by batch number;
• note the batch number in methods sections and data files;
• keep vials from different batches separate, and do not combine them into one stock without recording it;
• when results shift, check whether the batch changed.

What this means in Australia

• Labels and identity. The TGA has warned that labelling of unapproved peptide products may be inaccurate or misleading, and that products identified only by codes, or that do not clearly state the active ingredient and strength, pose significant risks ^[12]. It reports intercepting unlabelled vials at the border with no identifying information, and has said that “manufacture” includes applying a label to a blank vial ^[13].
• Regulatory status. A batch number and a matching certificate are evidence about quality. They do not change a product’s legal status. The TGA has stated that a “research use only” disclaimer does not make supply lawful, change regulatory status, permit importation, or remove advertising or supply obligations ^[12].
• GMP. For medicines, the TGA applies the PIC/S Guide to GMP, including its batch record and recall requirements ^[2]. See Good Manufacturing Practice Explained.

This is general information, not legal advice. Laws change; check the current Poisons Standard and TGA guidance.

Frequently asked questions

What is the difference between a batch number and a lot number?

None in GMP usage. ICH Q7 defines them as the same thing: a unique code that identifies a batch and from which its production and distribution history can be determined ^[1].

How is a vial matched to its certificate of analysis?

By comparing the batch number on the vial label with the batch number on the certificate, character for character, along with the compound, labelled amount and retest or expiry date ^[1].

What is a retention sample?

A fully packaged unit kept from a batch of finished product for identification purposes, such as checking its labelling and batch number. A reference sample is kept for analysis ^[3].

How long are batch records kept?

ICH Q7 recommends at least one year after the batch’s expiry date, or at least three years after complete distribution for materials with retest dates ^[1].

Why do batch numbers matter in a recall?

Distribution records list which batches went where, so a recall can be limited to the affected batch and reach everyone who received it ^{[2, 6]}.

References

1. International Council for Harmonisation. ICH Q7: Good manufacturing practice guide for active pharmaceutical ingredients. Sections 6.1, 6.5, 8.4, 9.4, 10.2, 11.4, 11.7, 15, 17.2 and Glossary. database.ich.org. Accessed 25 October 2026.
2. Pharmaceutical Inspection Co-operation Scheme. Guide to Good Manufacturing Practice for Medicinal Products, PE 009-17: Part I. Chapters 1, 4 and 8. 25 August 2023. tga.gov.au. Accessed 25 October 2026.
3. Pharmaceutical Inspection Co-operation Scheme. Guide to Good Manufacturing Practice for Medicinal Products, PE 009-17: Annexes. Annex 19, Reference and retention samples. 25 August 2023. tga.gov.au. Accessed 25 October 2026.
4. European Medicines Agency. Guideline on the development and manufacture of synthetic peptides. EMA/CHMP/CVMP/QWP/367182/2025. Adopted 4 December 2025; effective 1 June 2026. ema.europa.eu. Accessed 25 October 2026.
5. Greenberg MA. Serialization: benefits beyond regulatory compliance. Ther Innov Regul Sci. 2014;48(6):NP22–NP27. doi:10.1177/2168479014553034. PMID: 30227462
6. Therapeutic Goods Administration. Procedure for recalls, product alerts and product corrections (PRAC). tga.gov.au. Accessed 25 October 2026.
7. Therapeutic Goods Administration. Database of Recalls, Product Alerts and Product Corrections (DRAC). tga.gov.au. Accessed 25 October 2026.
8. Ghijs S, Wynendaele E, De Spiegeleer B. The continuing challenge of drug recalls: insights from a ten-year FDA data analysis. J Pharm Biomed Anal. 2024;249:116349. doi:10.1016/j.jpba.2024.116349. PMID: 39029352
9. de Marco A, Berrow N, Lebendiker M, et al. Quality control of protein reagents for the improvement of research data reproducibility. Nat Commun. 2021;12(1):2795. doi:10.1038/s41467-021-23167-z. PMID: 33990604
10. Biddle M, Stylianou P, Rekas M, et al. Improving the integrity and reproducibility of research that uses antibodies: a technical, data sharing, behavioral and policy challenge. MAbs. 2024;16(1):2323706. doi:10.1080/19420862.2024.2323706. PMID: 38444344
11. Choules MP, Bisson J, Simmler C, et al. NMR reveals an undeclared constituent in custom synthetic peptides. J Pharm Biomed Anal. 2020;178:112915. doi:10.1016/j.jpba.2019.112915. PMID: 31671336
12. Therapeutic Goods Administration. Understanding your responsibilities when importing, compounding and supplying unapproved peptide products. Safety advisory, 13 April 2026. tga.gov.au. Accessed 25 October 2026.
13. Therapeutic Goods Administration. Unapproved peptide product promoters and suppliers are put on notice. Media release, 20 July 2026. tga.gov.au. Accessed 25 October 2026.