Lot Traceability in Research Supply: Vial to COA

Lot traceability is the ability to follow a material through every step from manufacture to use, using its lot number as the common identifier. For a research lab, it means you can show exactly which batch of a reagent went into an experiment and retrieve the documents that describe it. This article covers how lots are defined and numbered, how to match a vial to its paperwork, and what happens when something goes wrong.

What a lot is, and why it matters

In quality-system terms, a batch or lot is a specific quantity of material produced in a defined process or series of processes so that it is expected to be homogeneous within specified limits. Test results on a certificate of analysis describe that lot and only that lot.

This is why lot identity matters so much. A COA from a different lot of the same product, however similar, does not document the material in your freezer. Purity, net peptide content, water content and counter-ion levels can all vary between lots.

Lots, sublots and aliquots

• Lot: the manufacturing unit described by one set of production and test records.
• Sublot or fill: a portion of a lot filled or packaged separately; good practice links it clearly to its parent lot.
• Aliquot: a portion you prepare in your own lab; it should carry the supplier lot number plus your own identifier.

How lot numbers are structured

There is no universal format, but most lot numbers encode enough information to be unique and to point to the underlying records. The table shows common elements; it is illustrative rather than a description of any specific supplier’s system.

Element	Illustrative example	Purpose
Product or material code	A short product prefix	Identifies what the material is
Date code	Year and month of manufacture	Supports chronological searching and stock rotation
Sequence number	-001, -002	Distinguishes lots made in the same period
Suffix	A letter for a sublot or fill	Links a portion back to the parent lot

Whatever the format, the lot number should be unique, never reused and printed legibly on the primary container label.

Chain of custody from manufacture to bench

Chain of custody is the documented sequence of who held a material and where, from production to final use. For research supply, the main links are:

1. Manufacture: production records identify starting materials, equipment and processing steps for the lot.
2. Testing: samples from the lot are analyzed, and results are reported on a COA that names the lot number and the laboratory.
3. Release and storage: the lot is approved, labeled and stored under defined conditions.
4. Distribution: the shipping record links each order to the lot or lots it contained.
5. Receipt and use: your lab records the lot on receipt and in every experiment that uses it.

A break at any link, such as relabeling without a record, or pooling two lots into one container, makes the material untraceable. The manufacturing process page describes the steps on the supplier side.

Lot traceability on receipt: matching vial, packing slip and COA

A short, consistent receiving check catches most mix-ups before they reach an experiment.

1. Compare the product name and lot number on each primary container with the packing slip.
2. Retrieve the COA for that lot number and confirm the lot, product name and any listed sequence or molecular formula match.
3. Note the date of the COA and any retest or expiry date.
4. Check the label for legibility and integrity; a damaged or missing label is a reason to quarantine.
5. Record the receipt date, lot number, quantity and storage location in your inventory system.
6. Keep a copy of the COA, or a controlled link to it, with your records.

Veridryx publishes lot-level COAs in its Testing Library, so you can look up the matching document by the lot number on the label. Our guide on how to read a certificate of analysis explains what to check once you have it.

Inside your own lab

• Label every aliquot or solution with the supplier lot, your aliquot ID, concentration, solvent, preparation date and initials.
• Do not combine material from different lots in one container.
• Record the supplier lot in the experimental record, not just the product name.
• Use first-expired, first-out rotation where expiry or retest dates apply.

Deviations, complaints and recalls

Traceability matters most when something unexpected happens. If a lot is found to be out of specification after distribution, or a lab reports an anomaly, the lot number determines who is affected.

How a supplier typically responds

• Open a deviation or complaint record and investigate root cause.
• Check retained samples from the lot and, where useful, retest.
• Use distribution records to identify every recipient of the lot.
• Notify affected customers and, if needed, request quarantine or return.
• Record corrective actions through a CAPA process, as described in quality-system frameworks such as ICH Q10.

What a lab should be able to do

When notified, you should be able to find every container from the lot, every aliquot made from it and every experiment that used it. Labs that record lot numbers consistently can answer that question in minutes. The documentation habits in our sibling article on ALCOA+ data integrity make this possible.

Record retention

Retention periods depend on the setting. For active pharmaceutical ingredients, ICH Q7 states that production, control and distribution records should be kept for at least one year after the expiry date of the batch, or at least three years after the batch is completely distributed for materials with retest dates. Research labs usually follow institutional, funder or contractual requirements instead.

Whatever the period, records must stay legible and retrievable. Electronic records need backups and a format that can still be read when the retention period ends.

Frequently asked questions

Can I use a COA from a previous lot of the same product?

No. A COA documents only the lot named on it. Results such as purity, net peptide content and water content can differ between lots.

What should I do if the lot number on the vial does not match the paperwork?

Quarantine the material, do not use it, and contact the supplier with photos of the label and the packing slip. Record the discrepancy in your receiving log.

Should aliquots carry the supplier lot number?

Yes. Each aliquot should carry the supplier lot plus your own aliquot identifier, so any result can be traced back to the original material and its COA.

References

1. ICH Q7 Good Manufacturing Practice Guide for Active Pharmaceutical Ingredients, Section 6: Documentation and Records.
2. ICH Q10 Pharmaceutical Quality System.
3. ISO 9001:2015 Quality management systems—Requirements, Clause 8.5.2: Identification and traceability.