What storage conditions are acceptable for urine specimens prior to analysis, and for how long?

What storage conditions are acceptable for urine specimens prior to analysis, and for how long?

• A. Refrigeration at 2-8°C for up to 7 days
• B. Room temperature for up to 7 days
• C. Freeze at -20°C only if longer than 7 days, with labeling
• D. Refrigeration at 4-10°C for up to 5 days

Answer: (A)

Preserving urine specimens before analysis hinges on slowing bacterial growth and chemical changes. Refrigerating at about 2-8°C slows microbial activity and enzymatic processes, helping to maintain the stability of drugs, metabolites, and urinary components for analysis. This temperature range is a practical compromise that keeps samples stable for up to roughly a week in routine testing.

Room temperature allows bacteria to multiply and many analytes to degrade or change, which can skew results. Freezing at -20°C is suitable for longer storage, but for short-term preservation (up to 7 days) refrigeration is preferred to avoid potential freeze-thaw issues and the need for immediate freezing logistics.