Retain Samples
Retain samples are portions of each batch — and often of key raw materials — kept under controlled conditions so the product can be re-examined after it ships.
On this page · 5 sections
How does Retain Samples apply to your shop floor?
Pick your industry and scale — Ask V5 rewrites the definition in your context, gives a worked example, and shows what V5 does on day one.
01What are retain samples?
Retain samples (also called retained samples, retention samples or reserve samples) are set aside from a batch and stored so the manufacturer can examine the same material later. If a customer complains, a stability question comes up or a regulator asks, the retain lets you test or inspect exactly what was shipped.
EU GMP Annex 19 separates two ideas: a reference sample is kept for analysis if needed, while a retention sample is a fully packaged unit kept for identification — for example, to confirm presentation and labelling. US regulations use the term reserve sample.
02Retain sample rules by regulation
| Regulation | What to keep | How long (summary) |
|---|---|---|
| 21 CFR 211.170 (US drugs) | Reserve samples of each lot of active ingredient and of each lot of drug product, at least twice the quantity needed for all required tests (except sterility and pyrogens) | Generally 1 year after the expiration date; specific rules for certain OTC and radioactive products |
| 21 CFR 111.83 (US dietary supplements) | Reserve samples of each lot of packaged and labelled supplement, in the same container-closure system, at least twice the quantity needed for tests | 1 year past the shelf-life date, or 2 years from distribution of the last batch if no shelf-life date |
| EU GMP Annex 19 | Reference samples of starting materials and finished product; retention samples of finished packaged product | Finished product generally at least 1 year after expiry; starting materials generally at least 2 years after release of product, with exceptions |
Food manufacturers are not always required by law to keep retains, but many customers and food safety schemes expect them, and retains make complaint investigations much faster.
03How to store retain samples
- Store under the labelled storage conditions of the product (21 CFR 211.170 and 111.83 both tie storage to label conditions).
- Use the same container-closure system as the marketed product, or one with the same characteristics.
- Label each retain with product, lot, date and retention end date; keep a log or system record.
- Restrict access to the retain library and record every removal.
- Visually examine drug reserve samples at least once a year for deterioration, as 211.170(b) requires, and investigate evidence of deterioration.
- Destroy retains only when the retention period has ended, and record it.
04Retain sample pulls
A retain sample pull is taking a retain out of the library — to test it for a complaint, to support an investigation, or to inspect its appearance. Good practice is to record who pulled it, why, how much was used, what was found and what remains. If the retain is used up, the remaining quantity may no longer meet the regulatory minimum, so many sites keep extra.
- Raise a request linked to the complaint, deviation or investigation.
- Locate the retain from the log by product and lot.
- Record the pull: person, date, quantity, reason.
- Test or inspect and link the results to the request.
- Return any remainder and update the log.
05Retain samples in V5
Frequently asked questions
Q.How long should retain samples be kept?+
For US drugs, generally 1 year after the lot's expiration date (21 CFR 211.170). For US dietary supplements, 1 year past the shelf-life date or 2 years from distribution if there is no shelf-life date (21 CFR 111.83). Check the exact rule for your product.
Q.How much should a retain sample be?+
US drug and supplement rules require at least twice the quantity needed to perform all required tests (drug rules exclude sterility and pyrogen tests).
Q.What is the difference between retain samples and reserve samples?+
They usually mean the same thing. US regulations say reserve samples; EU GMP Annex 19 distinguishes reference samples (for analysis) and retention samples (packaged units for identification).
Q.Do food manufacturers need retain samples?+
Not always by law, but many customers and food safety schemes expect them, and they make complaint investigations faster.
Q.Where should retain samples be stored?+
Under the product's labelled storage conditions, in the marketed container-closure (or equivalent), in a controlled area with a log of every removal.
Primary sources
Further reading
Want to see how Retain Samples could fit into your own records and workflows? Explore the related V5 pages or talk to our team about what applies to your operation.