Is a normal amount of urine in the bladder after voiding considered normal?

From the Guidelines

A normal amount of urine in the bladder after voiding is typically less than 50 ml, as the bladder is not designed to empty completely with each void. According to the most recent guideline on adult neurogenic lower urinary tract dysfunction, a post-void residual (PVR) measurement should be performed at the time of diagnosis and may be checked periodically thereafter to monitor for changes in bladder emptying ability, regardless of symptoms 1. Normal urine output is typically 800-2000 ml per day, with each void being about 200-400 ml. The bladder's normal capacity is about 400-600 ml, though the urge to urinate often occurs when the bladder contains about 150-200 ml of urine. Factors that affect urine production include fluid intake, environmental temperature, physical activity, and certain medications.

Key Points to Consider

• The American Urological Association (AUA) guideline on management of benign prostatic hyperplasia suggests that post-void residual urine (PVR) volume is an optional test for men who were considering therapy for bothersome lower urinary tract symptoms (LUTS) 1.
• Large PVR volumes (e.g., 350 ml) may indicate bladder dysfunction and predict a slightly less favorable response to treatment, but residual urine is not a contraindication to watchful waiting or medical therapy 1.
• If you're concerned about abnormal urination patterns such as frequent urination, urgency, pain, or incomplete emptying, these could indicate conditions like urinary tract infections, prostate issues in men, or pelvic floor dysfunction, and should be evaluated by a healthcare provider.
• Maintaining good hydration and regular bathroom habits helps support normal bladder function.

Recommendations for Evaluation

• A post-void residual measurement should be performed at the time of diagnosis and may be checked periodically thereafter to monitor for changes in bladder emptying ability, regardless of symptoms 1.
• An elevated PVR potentially associated with a clinically relevant abnormality or condition should be confirmed with a second measurement at another visit 1.

From the Research

Normal Amount of Urine and Bladder After Voiding

• The normal process of storing and passing urine can be disrupted, leading to urinary incontinence 2.
• A feeling of incomplete emptying with little post-void residual is a common complaint in patients with lower urinary tract symptoms 3, 4.
• Studies have shown that this feeling is not always correlated with an elevated post-void residual, especially in women 4, 5.
• In men, the sensation of incomplete bladder emptying is correlated with an elevated post-void residual, especially in those over 60 years old 5.
• Voiding problems can arise from abnormal storage of urine or problems with urinary control, and a better understanding of the physiology of urinary control could lead to preventive measures and appropriate therapeutic measures 2.

Factors Affecting Urine and Bladder Function

• Age can affect post-void residual volume, with men experiencing an increase in PVR volume by 0.65 mL per year of age 5.
• Voiding symptoms and urgency are associated with high PVR volume in men, while storage and voiding symptoms do not correlate with PVR volume in women 5.
• The relationship between lower urinary tract symptoms and post-void residual urine volume is complex and can vary between men and women 3, 4, 5.
• Dehydration can also affect urine output and bladder function, and its diagnosis requires an appraisal of the patient and laboratory testing, clinical assessment, and knowledge of the patient's history 6.