For longer storage periods, what temperature is preferable for serum samples?

When storing serum samples for extended periods, a temperature of -20°C is ideal. At this temperature, biochemical reactions are significantly slowed down, which helps preserve the stability and integrity of serum components, such as proteins, enzymes, and antibodies. This low temperature minimizes the risk of degradation, denaturation, or loss of biological activity of the analytes, allowing for more reliable results when the samples are eventually thawed and analyzed.

Storing serum samples at -4°C is not optimal for long-term preservation as it may not effectively prevent all enzymatic or microbial activity over time. Temperatures at or above 0°C, like 5°C, are suitable for short-term storage or transport but allow for potential degradation and changes in the sample composition if stored over longer periods. Hence, the use of -20°C is a standard practice in laboratories to ensure that serum samples maintain their quality and analytical accuracy throughout extended storage.