Which statement about cold chain requirements for certain tests is correct?

Which statement about cold chain requirements for certain tests is correct?

• A. All analytes require cold chain.
• B. Glucose specimens require 2–8°C transport.
• C. Some tests require cold chain, but the specific requirements depend on the test.
• D. Ammonia, lactic acid, and certain enzymes/hormones require 2–8°C during transport.

Answer: (D)

Maintaining a cold chain matters because some substances in blood and other specimens are unstable after collection and can change in concentration if the sample warms or sits too long. Ammonia and lactic acid are classic examples of analytes that rapidly shift with time at room temperature, so keeping the specimen at 2–8°C during transport slows those changes and preserves the true in-vivo levels. In addition, certain enzymes and some hormones can degrade or be altered outside of refrigerated conditions, making 2–8°C transport important for accurate results. While it’s true that some tests require cold chain and the specifics depend on the test, identifying concrete examples—ammonia, lactic acid, and certain enzymes/hormones—captures the practical reality of why cold chain is specified. Glucose handling, for instance, involves more nuanced practices beyond blanket 2–8°C transport, so stating that all glucose specimens require refrigeration isn’t universally correct.

Maintaining a cold chain matters because some substances in blood and other specimens are unstable after collection and can change in concentration if the sample warms or sits too long. Ammonia and lactic acid are classic examples of analytes that rapidly shift with time at room temperature, so keeping the specimen at 2–8°C during transport slows those changes and preserves the true in-vivo levels. In addition, certain enzymes and some hormones can degrade or be altered outside of refrigerated conditions, making 2–8°C transport important for accurate results.

While it’s true that some tests require cold chain and the specifics depend on the test, identifying concrete examples—ammonia, lactic acid, and certain enzymes/hormones—captures the practical reality of why cold chain is specified. Glucose handling, for instance, involves more nuanced practices beyond blanket 2–8°C transport, so stating that all glucose specimens require refrigeration isn’t universally correct.