Bladder Scan

Background

A bladder scan is a portable noninvasive ultrasound device that measures the volume of urine in the bladder by using ultrasound waves measured in three dimensions. The machine calculates a volume measurement of urine in the bladder without displaying an image on the screen. Bladder scans are used mostly during inpatient encounters to evaluate patients for urinary retention. Acute urinary retention (AUR) is defined as the inability to voluntarily pass urine, can cause severe pain, and is considered a medical emergency. Without prompt diagnosis and treatment, AUR can result in permanent damage to the kidneys and genitourinary system. AUR is more common in men than in women and is usually due to underlying benign prostatic hypertrophy (BPH). In women, urinary retention is usually due to pelvic organ prolapse or masses in the pelvis. The diagnosis of urinary retention is suspected when greater than 200 mL of urine is retained in the urinary bladder after the patient voluntarily voids. When the volume of urine in the bladder is greater than 100 mL, the bladder scan is 90% accurate compared with urinary bladder catheterization.