UDS provides objective measures related to bladder function and may be used when diagnostic uncertainty exists such as severe LUTS in a young man or in those with markedly elevated PVRs. UDS should be performed in a standardized manner adhering to good urodynamic practices.69 In patients with suspected neurogenic bladder, UDS is much more important as it is in other non-index situations such as patients with elevated PVR and diabetes mellites.70      UDS involves catheterizing the bladder and rectum and generally consists of filling cystometry and pressure flow voiding studies. In patients with LUTS/BPH, this is usually done to diagnose BOO and differentiate from other causes of LUTS. Due to the invasive nature and expense of this test, it has little utility in the initial evaluation of men with uncomplicated LUTS/BPH. In fact, UDS has not been shown to decrease rates of intervention in men randomized to UDS compared to men who underwent routine care, suggesting that it has a limited role in the diagnosis of uncomplicated LUTS/BPH.71 UDS may be useful in patient counseling because although it did not alter management, it did offer a better explanation of LUTS and aids as a tool in a shared decision context for patients to understand what to expect after surgical intervention. The penile cuff test (PCT) is a non-invasive pressure flow study which is used to estimate bladder pressure and has been used by some in the initial evaluation of men with LUTS/BPH. While it seems repeatable with reasonable accuracy at diagnosing BOO, a recent systematic review noted variability in definition of BOO and therefore UDS remains the diagnostic test of choice.72 Furthermore, a diagnosis of BOO, while possibly important for those undergoing surgical management, has little utility in the initial management of men with LUTS/BPH. It is certainly reasonable to use PCT in some scenarios, such as in a man with increasing PVR where a diagnosis of BOO might prompt intervention.