Which combination of tests is typically used to assess bladder outlet obstruction in men with LUTS?

• A. Cystoscopy
• B. Urinalysis and culture
• C. Uroflowmetry and post-void residual measurement; bladder scan
• D. Serum PSA

Answer: (C)

The key idea is using noninvasive, functional tests to measure how well urine flows and how much urine remains after voiding, which together reflect bladder outlet obstruction. Uroflowmetry provides the peak and average flow rates during urination, so you can see if the flow is abnormally low, a clue for obstruction or detrusor dysfunction. Post-void residual measurement, often done with a bladder scan, estimates how much urine is left in the bladder after voiding; a high residual suggests incomplete emptying, which is common with obstruction.

Taken together, these tests give objective, practical information about whether the outlet is causing a blockage and how severe it is, without immediately resorting to invasive visualization. Cystoscopy can visualize anatomy but is invasive and more about direct visualization than initial functional assessment. Urinalysis and culture screen for infection or stones but don’t quantify obstruction. Serum PSA assesses cancer risk, not bladder outlet function.