Final answer:
The best action if a urine specimen cannot be analyzed right away is to refrigerate it, and for ultra-long-term storage or transport, freezing at -70 °C or lower is necessary. Chemical preservatives are less ideal, and discarding or leaving the specimen at room temperature can compromise the sample.
Step-by-step explanation:
If a urine specimen cannot be analyzed immediately, the best course of action is to refrigerate the specimen. This is preferred because cold temperatures slow down the metabolic processes of any bacteria present and help preserve the constituents of the urine. Refrigeration at temperatures like 4 °C is ideal for short-term storage. However, if long-term preservation is required, the urine needs to be frozen. For ultra-long-term storage or for shipping, samples may be frozen at ultra-low temperatures of -70 °C or lower, using dry ice or liquid nitrogen tanks. Although adding a chemical preservative is an option, it can interfere with certain tests and is typically less ideal than refrigeration. Discarding the specimen and ordering a recollection should be a last resort, and setting the specimen aside at room temperature can result in the alteration of the urine components, rendering the sample unfit for accurate analysis.