Post-void residual (PVR) is the volume of urine left in the bladder immediately after you finish urinating. It is one of the simplest tests in urology and gynecology, and it answers a single, important question: is the bladder emptying?
How it is measured
The most common method is a quick bladder ultrasound held over the lower abdomen right after the patient empties. It is painless, takes under a minute, and gives a number in milliliters. If ultrasound is unavailable, a catheter can drain and measure the residual directly.
What is normal
There is no single universally accepted threshold, and ranges vary by source and patient age, but in broad terms:
- Under 50 mL: usually reassuring.
- 50 to 100 mL: borderline; clinicians often re-check.
- Over 100 mL: worth investigating, especially if symptomatic.
- Over 200 to 300 mL: significant retention; needs evaluation.
Why it matters
A high PVR means the bladder is not emptying completely. That can:
- Cause overflow incontinence (small leaks from a bladder that is constantly near full).
- Increase risk of urinary tract infections, because stagnant urine is a culture medium.
- Stress the upper urinary tract over time.
- Mimic overactive bladder symptoms, since the bladder always has limited room before the next urge.
What causes high PVR
In men, the most common cause is benign prostatic hyperplasia (BPH) obstructing outflow. In both sexes, it can come from a weak detrusor muscle (underactive bladder), neurological conditions, certain medications, or pelvic floor dysfunction. A clinician interpreting your PVR will look at it alongside symptoms, a bladder diary, and often a flow study or further imaging.