Normal Post-Void Residual Volume
A normal post-void residual (PVR) volume is less than 50 mL in most asymptomatic adults, with values up to 100 mL generally considered acceptable in clinical practice. 1, 2
Defining Normal PVR Values
In asymptomatic perimenopausal and postmenopausal women, the median PVR is 19 mL (range 0-145 mL), with 95% having PVR ≤100 mL and only 15% exceeding 50 mL. 2
The American Urological Association guidelines indicate that PVR <100 mL represents normal bladder emptying, and if measured consecutively 3 times at this level, monitoring can be discontinued. 1
Community-dwelling men show considerable variability in PVR measurements over time, with a median annual increase of only 2.2%, though individual variation is substantial. 3
Clinically Significant Thresholds
Large PVR volumes (>200-300 mL) indicate significant bladder dysfunction and predict less favorable treatment responses. 1, 4
PVR volumes >180 mL in asymptomatic adult men carry an 87% positive predictive value for bacteriuria, placing them at high risk for urinary tract infections. 5
The threshold of 150 mL is commonly cited but lacks strong evidence—voiding dysfunction can occur even with PVR <150 mL, as demonstrated in women where 18 of 20 patients with confirmed voiding dysfunction had PVR <150 mL (range 0-50 mL). 6
No specific PVR "cut-point" has been established for clinical decision-making due to marked test-retest variability and lack of appropriately designed outcome studies. 1
Measurement Considerations
PVR measurement should be repeated at least once (ideally 2-3 times) to confirm abnormal findings due to marked intra-individual variability. 1, 4
The interval between voiding and PVR measurement should be short (within 30 minutes), and ultrasound bladder volume measurement is preferred over urethral catheterization. 1, 4
In children, repeat flow/residual urine measurement up to 3 times in the same setting in a well-hydrated child is recommended for confirmation. 1
Clinical Decision Points
PVR <100 mL: Normal bladder emptying; no intervention required. 1
PVR 100-200 mL: Borderline elevation; initiate intermittent catheterization and monitor for urinary tract infections, particularly in patients with overactive bladder considering botulinum toxin therapy. 1
PVR >200-300 mL: Significant bladder dysfunction; implement intermittent catheterization every 4-6 hours and evaluate for underlying causes including bladder outlet obstruction, neurogenic bladder, and medication effects. 1, 4
PVR >999 mL: Severe urinary retention requiring immediate catheterization to prevent bladder damage and post-obstructive nephropathy. 7
Important Caveats
PVR values between 0-300 mL do not predict response to medical therapy for benign prostatic hyperplasia. 1
No level of residual urine, in and of itself, mandates invasive therapy—clinical decision-making must incorporate symptoms, quality of life impact, and risk of complications. 1, 8
Baseline increased PVR predicts rapid decrease in voided volume, consistent with bladder outlet obstruction contributing to detrusor overactivity and decreased bladder compliance. 3