The lot number printed on a vial of bacteriostatic water is the single piece of information that connects the vial in your hand to the water system it came from, the day it was filled, the tests it passed and every other vial that shares its history. Traceability is the practice of keeping that connection intact through your own laboratory.
What a lot is
A lot (or batch) is the set of vials filled from one prepared bulk solution in one filling operation. Everything about the lot is shared: the water, the preservative addition, the filling environment, the container components, and the samples pulled for sterility, endotoxin, pH, assay and particulate testing. The certificate of analysis describes the lot, not the individual vial, which is why the lot number on the COA must match the vial. See how to read a COA.
Why traceability matters
- Investigations. If a preparation gives an unexpected result, or a vial is found cloudy, the first question is which lot it came from and what else that lot touched. Without a record, the investigation stops before it starts.
- Reproducibility. Recording the lot of every material in a preparation lets a result be repeated with the same inputs, or a difference between two runs be traced to a lot change.
- Recalls and notices. If a supplier issues a notice about a lot, you need to know within minutes whether you hold it, where it is, and what it has been used for.
- Expiration management. Lot and expiration go together; a lot log is also a first-expiring, first-out tool.
A minimal traceability record
A spreadsheet or inventory system with one row per lot received is enough for most laboratories:
| Field | Example |
|---|---|
| Product and size | Bacteriostatic water, 10 mL |
| Lot number | as printed on vial |
| Expiration date | as printed on vial |
| Quantity received | 36 vials |
| Date received; inspected by | date; initials |
| COA on file | yes / file reference |
| Storage location | cabinet, shelf |
| Issued to (bench, date, quantity) | running entries |
| Quantity remaining | running total |
At the bench
Two habits complete the chain. First, write the date of first puncture on each vial when it is opened, together with the 28-day discard date. Second, record the lot number in the notebook or batch record of every preparation the vial contributes to. That takes seconds and is the only way a result can later be connected to a lot.
Single-lot supply for studies
Where a study must not change materials mid-course, order enough from one lot to complete it and reserve that lot for the project. Suppliers can usually confirm single-lot availability for a given quantity before shipping; ask. Guidance for institutional purchasers is in buying for institutional laboratories.
When a lot is questioned
- Quarantine remaining vials of the lot; do not discard them until the question is resolved.
- Pull the COA and the receiving record.
- List every preparation the lot was issued to, from bench records.
- Contact the supplier with the lot number, the observation and photographs if relevant.
Most questions resolve to handling rather than the lot, but the record is what makes that determination possible. Related: can bacteriostatic water go bad, vetting a supplier.
Every vial BAC Water Supply ships is labeled with its lot number and expiration date, with batch documentation available on request.
All BAC Water Supply products are supplied for laboratory research use only and are not for human or veterinary use.