3. Bladder Ultrasound Protocol

Step 3: Calculate Bladder Volume

Tip: Ultrasound can be used to estimate bladder volume using a simple to remember formula: Height x Width x Length x 0.7

  • The Width and Depth of the bladder are measured in the transverse view.
  • The superior-inferior dimension (Height) is measured in the longitudinal view.
  • Most ultrasound machines will automatically calculate the entire bladder volume which should be less than 300-400 mL in healthy adults and Post Void Residual (PVR) should be less than 50-100mL (Fitzgerald; Latini).

The actual formula used to calculate bladder volume is Width x Depth x Height x Correction Coefficient. If you want more accurate bladder volume measurements, you can use the correction coefficient that most closely corresponds to the patient’s bladder shape.

The table below shows you the correction coefficient for each of the bladder shapes:

Bladder ShapeCorrection Coefficient
Unknown0.72 (most commonly used)
Triangular prism0.66
Cylinder (Ellipsoid)0.81
3. Bladder Ultrasound Protocol

Step 2: Bladder Ultrasound – Transverse View

  • Next, center the bladder and then rotate the transducer 90 degrees counterclockwise. The indicator should now point to the patient’s Right side.
  • Make sure to tilt the ultrasound probe so it scans into the pelvic cavity.
Transverse View Bladder Ultrasound Probe Position
Transverse View
  • In the transverse view, identify the BladderUterus (females), Prostate (males), and Rectum.
Female Bladder Ultrasound – Longitudinal View
Bladder Ultrasound - Male Transverse
Male Bladder Ultrasound – Longitudinal View
  • Tilt/Fan the probe to examine the entire bladder from superior to inferior.
tilting-transverse-bladder ultrasound
Transverse view of a full bladder
3. Bladder Ultrasound Protocol

Bladder Ultrasound Protocol

Step 1: Bladder Ultrasound – Longitudinal View

  • Place the transducer with the indicator pointing towards the patient’s head in the patient’s midline, right above the pubic symphysis.
  • Rock the probe so that it points down towards the pelvic cavity.
Sagittal-Longitudinal View Bladder Ultrasound Probe Position
Bladder Ultrasound – Longitudinal View

Tip: One of the most important things to remember when performing bladder ultrasound is that the bladder is directly posterior to the pubic bone/symphysis. If you are unable to get proper images, most likely your ultrasound probe is placed too superiorly.

In the longitudinal (sagittal) view, identify the BladderBowel GasUterus (females), Prostate (males), and Rectum.

Bladder Ultrasound - Female Longitudinal
Female Bladder Ultrasound – Longitudinal View
Male Bladder Ultrasound – Longitudinal View
  • Observe the lateral borders of the bladder by tilting/fanning the probe left and right.
tilting-longitudinally-bladder ultrasound
Tilting the probe in the longitudinal view