If serum or plasma sample will be delayed longer than 4 hours, at what temperature should it be stored?

If serum or plasma sample will be delayed longer than 4 hours, at what temperature should it be stored?

• A. Room Temperature (20-25 C)
• B. 4 to 6 C
• C. -20 C
• D. 60 C

Answer: (B)

Storing serum or plasma at 4 to 6 degrees Celsius is best when processing will be delayed beyond four hours because refrigeration slows cellular metabolism and enzymatic activity that can alter analyte levels. At room temperature, processes like glycolysis and other enzymatic reactions continue, which can change concentrations of things measured in the sample and lead to inaccurate results. Freezing at -20°C is useful for long-term storage, but it isn’t ideal for a sample that will be tested after a short delay because thawing can introduce variability and some analytes can be affected by freeze-thaw cycles. Heating to 60°C would damage proteins and many analytes, so it’s unsuitable.

Storing serum or plasma at 4 to 6 degrees Celsius is best when processing will be delayed beyond four hours because refrigeration slows cellular metabolism and enzymatic activity that can alter analyte levels. At room temperature, processes like glycolysis and other enzymatic reactions continue, which can change concentrations of things measured in the sample and lead to inaccurate results. Freezing at -20°C is useful for long-term storage, but it isn’t ideal for a sample that will be tested after a short delay because thawing can introduce variability and some analytes can be affected by freeze-thaw cycles. Heating to 60°C would damage proteins and many analytes, so it’s unsuitable.