What is the main factor to preserve urine specimens for analysis?

Refrigeration is crucial for preserving urine specimens for analysis because it helps slow down the growth of bacteria and inhibits the breakdown of certain analytes that can occur at room temperature. When urine is collected, it is prone to changes in its composition due to microbial activity and chemical reactions. By refrigerating the specimen, the integrity of the sample is maintained, allowing for more accurate test results when the analysis is eventually performed.

Although other methods, like adding preservatives or immediate analysis, can aid in preservation, refrigeration is a straightforward and effective approach that is widely adopted in laboratory practices. Immediate analysis is not always practical, especially in settings where transportation or delays are unavoidable. Covering in ice can keep the temperature low but is less efficient and may not provide consistent cooling compared to standard refrigeration. Therefore, refrigeration is recognized as the most reliable method for preserving urine specimens until they can be analyzed.