From the Research
The normal post-void residual (PVR) bladder volume for a 15-year-old female patient should be less than 20 mL when measured by ultrasound, as indicated by the most recent and highest quality study available 1. This value represents the amount of urine remaining in the bladder after normal voluntary urination. For adolescents, a PVR of less than 20 mL is generally considered normal, though some sources accept values up to 30 mL. These values are based on pediatric urology guidelines and clinical practice. The measurement is important because elevated post-void residual volumes may indicate urinary retention, which can be caused by various conditions including neurogenic bladder, urinary tract infection, or anatomical abnormalities. When performing the ultrasound, it's essential to measure the PVR within 5-10 minutes after voiding for accurate results. If elevated values are found, a repeat measurement may be warranted to confirm the finding before further investigation. Some key points to consider when evaluating PVR in adolescents include:
- Age and gender-specific nomograms for single and dual post-void residual urine in healthy children, as established in the study by 1
- The importance of considering bladder capacity and voiding patterns when interpreting PVR results, as discussed in the study by 2
- The use of pelvic floor ultrasound as a diagnostic tool for evaluating insensible urinary incontinence, as explored in the study by 3
- The role of urodynamic tests, such as cystometry and uroflowmetry, in evaluating lower urinary tract dysfunction, as described in the study by 4
- The formula for calculating bladder volume: length × width × height × 0.52, with measurements taken in three dimensions, as mentioned in the example answer. However, the most recent and highest quality study available 1 provides the most relevant guidance for determining normal PVR values in adolescents.