What is recommended to preserve urine samples for microscopy?

• A. Refrigeration at 2–8°C or prompt analysis; keep sample sealed and avoid delays to prevent precipitation or bacterial growth.
• B. Freeze at -20°C.
• C. Add formalin.
• D. Leave at room temp for 24 hours.

Answer: (A)

Preserving urine for microscopy hinges on keeping the sediment stable and free from changes that would mislead interpretation. Refrigerating the specimen at 2–8°C slows bacterial growth and chemical changes, and analyzing promptly avoids alterations in cells, casts, and crystals. Keeping the sample sealed prevents contamination and evaporation, which can concentrate or dilute elements and change sediment appearance.

Freezing is not ideal because rapid freezing can rupture cells and artifacts can form, distorting morphology. Adding formalin fixes specimens but can alter cellular and sediment structures, interfering with routine microscopic identification. Leaving urine at room temperature allows bacteria to multiply and sediments to change or precipitate, leading to inaccurate results.

So, refrigerate or analyze promptly, and keep the sample sealed to maintain accurate microscopic evaluation.