What is considered an abnormal post-void residual (PVR) volume?

Abnormal Post-Void Residual (PVR) Volume

A post-void residual (PVR) volume greater than 100-200 mL is generally considered abnormal and requires clinical attention, with values above 180 mL associated with significantly increased risk of bacteriuria. 1

Normal PVR Values

• Normal PVR should be less than 50 mL in healthy young men 1
• PVR may increase slightly with age, but mean values remain relatively stable across different age groups in healthy men 1
• For adolescents, age and gender-specific values apply:
  • Males: >30 mL (or >8-11% of bladder volume) requires further investigation
  • Females: >35-45 mL (or >11-13% of bladder volume) requires further investigation 2

Clinical Significance of Different PVR Thresholds

100-200 mL: Caution Threshold

• PVR of 100-200 mL is considered a threshold requiring caution before botulinum toxin therapy for overactive bladder (OAB) 3
• This range indicates potential bladder dysfunction that may require monitoring

>180 mL: Bacteriuria Risk

• A PVR of 180 mL or greater has been associated with an 87% positive predictive value for bacteriuria in some studies 4
• However, other research has questioned this specific cutoff, finding only 28% sensitivity with 94% specificity for predicting UTI 5

>350 mL: Significant Dysfunction

• PVR volume >350 mL may indicate significant bladder dysfunction and predict less favorable response to treatment 1

Clinical Implications

For OAB Treatment

• PVR should be measured prior to intradetrusor botulinum toxin therapy 3
• Caution should be used when performing botulinum toxin injection in patients with a PVR >100-200 mL 3
• PVR should be reassessed if symptoms worsen after botulinum toxin injection 3

For Urethral Stricture Evaluation

• Elevated PVR should prompt consideration of urethral stricture in the differential diagnosis 3
• Follow-up after stricture treatment should include PVR measurement to assess treatment success 3

Measurement Considerations

• Ultrasound bladder volume measurement is preferred to urethral catheterization 6
• The interval between voiding and PVR measurement should be short 6
• PVR measurements show significant intra-individual variability, requiring repeated measurements for confirmation 1
• Calculated PVR by subtraction is less reliable than direct measurement, with almost half of patients with PVR >200 mL being miscategorized as normal when using subtraction methods 7

Pitfalls and Caveats

• A single elevated PVR measurement should be confirmed with a second measurement at another visit 1
• No universally accepted definition of a significant residual urine volume exists 6
• PVR alone does not specifically indicate bladder outlet obstruction 6
• PVR is not a strong predictor of acute urinary retention 6
• Measurement technique matters: transabdominal ultrasound is the preferred non-invasive method 1

When evaluating PVR, consider the patient's age, gender, and clinical context. While 100-200 mL serves as a general threshold for concern, values above 180 mL warrant closer monitoring due to increased risk of bacteriuria, and values above 350 mL suggest significant dysfunction requiring intervention.