What is the main reason to keep urine specimens refrigerated?

Keeping urine specimens refrigerated is primarily done to prevent the growth of microbes. When urine is left at room temperature, it can become a breeding ground for bacteria and other microorganisms. These microbes can alter the composition of the urine, potentially affecting test results and leading to misleading diagnoses. By refrigerating the urine, the metabolic activity of these organisms is slowed down, thereby maintaining the integrity of the sample for accurate laboratory analysis.

Preserving the urine at lower temperatures ensures that any chemical, physical, or microbiological changes that might occur over time are minimized. This is important because many laboratory tests require fresh specimens to provide reliable results. For example, certain constituents in urine can decompose or change due to bacterial activity, influencing values for tests that measure concentrations of substances within the urine.

While maintaining color, odor, and pH balance are important aspects of urine analysis, refrigeration is specifically critical for controlling microbial growth, which directly affects overall specimen quality.