Which device is appropriate for storing reagents at about 4 C?

• A. Refrigerator
• B. Freezer
• C. Incubator
• D. Cryostat

Answer: (A)

Storing reagents at 4 C relies on keeping them cool but not frozen, to slow degradation without causing ice damage. A refrigerator maintains roughly 2–8 C, which is ideal for many common reagents such as antibodies, buffers, and enzymes used in histology workflows. This temperature range preserves activity and stability over a practical time frame for routine use.

Using a freezer would push temperatures below freezing, which can damage or alter some reagents, cause precipitation, or require additional thawing steps. An incubator maintains higher temperatures designed to promote biological activity or growth, which would rapidly degrade or alter reagents stored at 4 C. A cryostat is meant for cutting frozen tissues and isn’t suitable for storage.

Keep reagents in the fridge with proper labeling, consider aliquoting to minimize freeze–thaw cycles if you must extend storage, and follow manufacturer guidelines for shelf life.