Uroflow reflects the velocity of a fluid as it moves through the urethra. It is a screening study; does not involve instrumentation, and provides information about normal versus abnormal voiding. Guidelines from the American Urological Association recommend 2 separate uroflowmetry tests with a voided volume > 150 ml for accurate interpretation.
A recent article by Chandrapal and colleagues (2016) highlighted a common problem with uroflows, inadequate voided volumes. They found in their clinic-based setting that voided volumes > 50% (63%) of clinic based uroflowmetry tests (n=169) were 150 ml or less. Basically these are non-interpretable per AUA guidelines. What is even more disturbing is the effort this group put in to try to ensure adequate voided volumes. They reminded the patient to come in with a full bladder at the next appointment on the appointment reminder card or courtesy telephone call, placed visual signs on all bathroom doors and on the reception desk to request that patients wait to void until after the appointment. Do these sound familiar? Yes, we all do these to ensure that voided volume uroflowmetry is adequate.
These authors make some suggestions to improve adequate voided volume at time of testing. The use of oral furosemide 20 mg which I believe to be unrealistic or doable in most offices. The second suggestion is definitely a possibility, bladder scan the patient prior to uroflow to determine adequate urine volume. If inadequate, the test could be delayed till patient consumes more fluids and reaches an adequate volume. We all have Bladder Scanners in our practices and this is a simple quick test to do. The authors had a third, but even more unrealistic suggestion, which is to catheterize the patient and fill the bladder with fluid to volume is reached.
This article is an important as it addresses a common procedure performed in urology practices.
Chandrapal, J. et al High Rates of Inadequate Urine Volume Cause Failure of Clinic Based Uroflowmetry in Men with Lower Urinary Tract Symptoms. Urology Practice. 2016, July 3:247-250. http://dx.doi.org/10.1016/j.urpr.2015.08.003
Written by: Diane K. Newman, DNP, Adjunct Professor of Urology in Surgery, Research Investigator Senior and Co-Director, Penn Center for Continence and Pelvic Health
University of Pennsylvania, Division of Urology, 3400 Spruce Street, 3rd Floor Perelman Bldg, Philadelphia, PA. 19104