What PVR threshold suggests abnormal incomplete bladder emptying warranting further evaluation, and how is PVR commonly measured?

• A. PVR > 200 ml; measured via ultrasound bladder scanner or catheterization after voiding
• B. PVR > 50 ml; measured by MRI
• C. PVR > 400 ml; measured by x-ray
• D. PVR > 1500 ml; measured by ultrasound only

Answer: (A)

Post-void residual (PVR) is the amount of urine left in the bladder after urination. A value that is clearly larger than what’s expected for normal bladder emptying indicates incomplete emptying and warrants further evaluation to look for causes such as bladder outlet obstruction, detrusor (bladder muscle) underactivity, or neurogenic issues.

The most practical and common way to measure PVR is noninvasively with a bladder ultrasound scanner (bladder scan) soon after voiding. If needed, a straight catheter can be used to drain the bladder and determine the residual volume. These methods are standard in clinical practice because they are quick, accessible, and accurate.

Other options like MRI or X-ray aren’t typical for routine PVR assessment, and certain proposed thresholds in some choices (either too low or too high) don’t align with how PVR is used in practice. The key point is that an abnormal, clinically significant residual after voiding is identified by a sizable amount of urine remaining, and it’s most commonly measured with bladder scanning or catheterization after voiding.