Scope
This article covers storage of laboratory materials in their supplied form. It does not cover preparation of solutions for administration, and gives no protocol for any use in humans or animals. Materials described in this catalog are not supplied for those purposes.
A specification describes material at release. Whether that specification still describes the material at the point of use depends entirely on what happened in between, and most of that period is under the receiving laboratory's control rather than the supplier's.
Moisture is usually the first problem
Lyophilised material is hygroscopic. The most common way water is introduced is not humidity in the freezer but condensation on a cold container opened in a warm room. Allowing a container to equilibrate to ambient temperature before it is opened removes that pathway, and costs nothing but patience.
Desiccant supplied with the material is part of the storage condition, not packaging. Discarding it changes the conditions the retest period was set under.
Temperature excursions
An excursion is a departure from the stated storage condition, and its significance depends on magnitude, duration, and how many have accumulated — not on whether the material still looks unchanged. A single brief excursion on delivery is a different matter from a freezer that cycles above its set point nightly.
- Record excursions when they are observed, including duration and approximate temperature. An unrecorded excursion cannot be assessed later.
- Monitored storage is worth more than nominally correct storage: a freezer with a logger is auditable, a freezer without one is an assumption.
- Where an excursion is material, the supplier's technical contact can advise whether the specification is still supportable for that lot. That is a lot-specific question.
Light and photosensitive labels
Fluorophore-labeled materials degrade under ambient laboratory lighting on a timescale of hours to days depending on the label. Amber containers and foil overwrap are the control; both need to remain in place during handling, not only during storage, which is where the requirement is most often lost.
Retest periods are conditional
A retest date is valid only under the stated storage condition. Material stored outside that condition has no supported retest date regardless of what the label reads, and re-establishing one requires re-testing rather than reasoning.
References
- OSHA Hazard Communication Standard, 29 CFR 1910.1200U.S. Department of Labor, Occupational Safety and Health Administration
- ISO/IEC 17025:2017 — General requirements for the competence of testing and calibration laboratoriesInternational Organization for Standardization
References are cited as the standards and guidance this note is written against. Citing a standard is not a claim of conformance to it.
Scope
This note covers documentation, procurement, storage, and analytical practice for laboratory and manufacturing materials. It is not guidance for preparing or using any material in a person or an animal, and nothing in this catalog is supplied for that purpose.