During a 24-hour urine collection, what is done with the first urine of the day?

During a 24-hour urine collection, what is done with the first urine of the day?

• A. It is discarded
• B. It is saved for testing
• C. It is warmed to room temperature
• D. It is mixed with the rest

Answer: (A)

Establishing a defined 24-hour window is essential. The first urine of the day is discarded to mark the start of the collection period, so that all urine collected afterward represents a complete 24-hour interval. By starting fresh this way, the results reflect only the urine produced during that defined time frame. All subsequent urine is saved and combined for testing. Warming it or keeping the first void separate would not align with how the timing and volume are measured, and mixing the first void with the rest would blur the start point of the collection.

Establishing a defined 24-hour window is essential. The first urine of the day is discarded to mark the start of the collection period, so that all urine collected afterward represents a complete 24-hour interval. By starting fresh this way, the results reflect only the urine produced during that defined time frame. All subsequent urine is saved and combined for testing. Warming it or keeping the first void separate would not align with how the timing and volume are measured, and mixing the first void with the rest would blur the start point of the collection.