Which of the following values best represents a normal post-void residual in adults?

• A. Less than 50 mL
• B. 60 mL
• C. 150 mL
• D. 250 mL

Answer: (A)

Post-void residual reflects how much urine remains in the bladder after finishing urination. It’s measured with a bladder scan/ultrasound or by catheterization. In healthy adults, the residual should be very small, typically less than 50 mL. A value around 60 mL is higher than normal and may indicate some incomplete emptying or weaker bladder contraction, especially if seen repeatedly. Residuals of 150 mL or more are clearly abnormal and suggest significant issues such as bladder outlet obstruction or poor detrusor function, with higher risks for infections or other complications. Therefore, the value that best represents a normal post-void residual is less than 50 mL.