How should colony-stimulating factors be stored?

• A. They should be stored in the refrigerator and not shaken.
• B. Room temperature.
• C. In the freezer.
• D. In direct sunlight.

Answer: (A)

Colony-stimulating factors are protein-based therapies, so they need cold storage to stay stable and preserve potency. Keeping them in the refrigerator (about 2–8°C) slows degradation, and avoiding shaking helps prevent denaturation or aggregation of the protein. Freezing can damage the protein and its container, and exposure to direct sunlight or heat can degrade it, so those options aren’t appropriate. If the product is a lyophilized powder, reconstitute per the instructions and then refrigerate.