Medical tests that doctors use to evaluate urine retention include cystoscopy, computerized tomography scans, electromyography and urodynamic tests, explains the National Institute of Diabetes and Digestive and Kidney Diseases. A doctor diagnoses acute urinary retention with a physical exam and postvoid residual measurement.
Cystoscopy involves using a cystoscope to look inside the bladder, which helps to determine the presence of a blockage or a stricture, explains the NIDDK. Urodynamic testing involves several tests, including pressure flow study, uroflowmetry and video urodynamics, to determine the function of the bladder and urethra. During an electromyography, doctors use specific sensors to measure the electrical activity of the muscles surrounding the bladder.