Uroflowmetry

• Alternative Names

  Uroflow

• How the test is performed

  You will urinate in a special urinal or toilet with a machine that has a measuring device.

  You will be asked to begin urinating after the machine has started. When you finish, the machine will create a report for your health care provider.

• How to prepare for the test

  Your health care provider may ask you to temporarily stop taking medications that can affect the test results.

  Uroflowmetry is best done when you have a full bladder. Do not urinate for 2 hours before the test. Drink extra fluids so you will have plenty of urine for the test.

  Do not place any toilet tissue in the test machine.

• How the test will feel

  The test involves normal urination, so you should not experience any discomfort.

• Why the test is performed

  This test is useful in evaluating the function of the urinary tract.

• Normal Values

  Normal values vary depending on age and sex:

  • Ages 4 - 7
    • The average flow rate for both males and females is 10 mL/sec.
  • Ages 8 - 13
    • The average flow rate for males is 12 mL/sec.
    • The average flow rate for females is 15 mL/sec.
  • Ages 14 - 45
    • The average flow rate for males is 21 mL/sec.
    • The average flow rate for females is 18 mL/sec.
  • Ages 46 - 65
    • The average flow rate for males is 12 mL/sec.
    • The average flow rate for females is 15 mL/sec.
  • Ages 66 - 80
    • The average flow rate for males is 9 mL/sec.
    • The average flow rate for females is 10 mL/sec.
• What abnormal results mean

  Results are compared with your symptoms and physical exam. A result that may need treatment in one patient may not need treatment in another patient.

  Several circular muscles normally regulate urine flow. If any of these muscles becomes weak or stops working, you may have an increase in urine flow or urinary incontinence.

  If there is a bladder outlet obstruction or if the bladder muscle is weak, you may have a decrease in urine flow.

  Your health care provider should explain and discuss any abnormal results with you.

• What the risks are

  There are no risks with this test.

Review Date: 9/7/2008

Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and Louis S. Liou, MD, PhD, Assistant Professor of Urology, Department of Surgery, Boston University School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.