Traces: making sense of urodynamics testing--Part 2: uroflowmetry

Uroflowmetry is an electronic recording of urinary flow. It is typically measured by one of two types of transducers. One type measures the weight of urine as it falls into a beaker or container placed on the transducer, and the other uses a spinning disc to measure urinary flow. Uroflowmetry is a non-invasive, comparatively inexpensive study often used to identify voiding abnormalities. Experienced clinicians can use uroflow tracings to differentiate a continuous (normal) flow pattern from abnormal patterns. While uroflowmetry has been found to reliably distinguish normal from abnormal flow patterns, uroflowmetry does not reliably distinguish the underlying cause of voiding abnormalities. Differential diagnosis of poor detrusor contraction strength from bladder outlet obstruction relies on a voiding pressure flow study that combines uroflowmetry with the various pressure studies used to generate a cystometrogram and pelvic floor muscle electromyography.