Storing veterinary medicines and laboratory reagents: the four questions that matter

2026-09-12 · medixanimals

Storage is where a product's stated shelf life either holds or quietly stops being true. Most storage problems in a clinic or a laboratory come down to four questions, and none of them are difficult — they are just easy to stop asking.

1. What range does this product actually require?

Products fall into three broad storage classes:

| Class | Typical range | Common examples | | --- | --- | --- | | Ambient | roughly 15–25 °C | many tablets, consumables, most equipment | | Refrigerated | roughly 2–8 °C | many biologicals, some reagents and diagnostics | | Frozen | −20 °C or below | certain reagents and controls |

The ranges above are typical, not universal. The authority is the manufacturer's label and the product's documentation, and a product can be an exception to the pattern its category suggests. "It's a reagent so it goes in the fridge" is a guess, not a storage decision.

2. Is the storage location actually holding that range?

A domestic fridge in a staff room is a different instrument from a qualified pharmaceutical refrigerator. The failure mode is not usually a dramatic breakdown; it is a unit that sits at 9 °C because it is overfull, or that swings every time the door opens at lunchtime, or that freezes stock at the back of the top shelf.

Two habits catch nearly all of it:

• Monitor continuously, not by glance. A minimum/maximum thermometer or a logger tells you what happened overnight; a dial tells you what is happening while you are looking at it.
• Leave air space. Cold storage relies on circulation. A fridge packed to the door has hot spots and cold spots, and the stock in them is not at the temperature the label requires.

3. What else does this product need besides temperature?

Temperature dominates the conversation, but it is not the only condition:

• Light. Some products are supplied in amber containers or foil for a reason. Decanting them into a clear container for convenience removes the protection.
• Moisture. Desiccant sachets in a container are part of the product. Tablets that absorb moisture can change physically long before the expiry date.
• Contamination and cross-contact. Food, specimens and reagents sharing a refrigerator is a problem regardless of temperature.
• Upright storage. Some formats depend on it, and it is rarely stated twice.

4. What happens when a product has been stored outside its range?

This is the question that matters most, because it is the one usually answered informally.

A temperature excursion is not automatically a disposal. It is a decision that needs three pieces of information: how far outside the range, for how long, and what the manufacturer says about excursions for that product. Some products tolerate a defined excursion; others do not tolerate any.

The workable process is:

1. Quarantine first. Physically separate the stock and mark it as not for use. The most common failure is leaving it on the shelf "until someone checks", by which point someone has used it.
2. Record what happened. Duration, temperature reached, which lots were affected. A vague memory is not enough for the manufacturer to give you a usable answer.
3. Ask the manufacturer or supplier. With the lot number and the excursion details, not without.
4. Record the decision. Whatever the outcome, the record is what protects the next person who wonders whether that stock was ever checked.

The one thing worth systematising

Every item above depends on knowing which lot you are talking about. If the storage record says "the refrigerator was out overnight" but nothing records which lots were in it, the safe answer is to discard everything — which is expensive, and avoidable with a receiving record that ties each lot to a location from the day it arrives.

This article is general information about storage practice. It is not veterinary advice and does not state the storage requirements of any particular product. Always follow the manufacturer's labelling and documentation, and consult a licensed veterinarian about the care of an animal.