What is Urine Flow Rate Test?

What is urine flow rate test?

You may be unfamiliar with the term urine flow rate or urinary flow rate, which is a common medical term in urology. Put it simply, the rate of urine flow measures how fast urine flows, how much it flows out, and how long it takes. It is expressed in ml/s.

Urine flow rate test is done mainly when the following symptoms appear:

• bladder residual urine increase
• urinary flow interruption
• increased frequency to urinate during night
• urinary incontinence

Urine flow rate test is an auxiliary test used to check whether the bladder functions normally. In clinical practice, urine flow per second during urination is recorded and plotted as a curve to analyze whether the lower urinary tract is obstructed. According to the urine flow rate curve, the parameters of urine flow rate are calculated, including maximum urine flow rate, urine flow time, average urine flow rate, maximum urine flow rate time, 2-second urine flow rate and total urine volume.

These are professional terms, and you may not understand them very well. In the above items, you can remember the maximum urine flow rate. When the urine volume is above 200ml, the maximum urine flow rate of normal men is >20 ~ 25ml/s, and for women it is 25 ~ 30ml/s. It is generally believed that obstruction can be ruled out if the maximum urine flow rate is above 25 ml per second. When it is below 10 ml per second, it indicates the possibility of obstruction; In between is suspected obstruction.

Urine flow rate is a noninvasive and relatively inexpensive test. It is an essential test of choice for most patients with suspected lower urinary tract dysfunction. The tests are normally done using uroflowmetry and bladder scanner together.