Digital rectal examination
The digital rectal examination (DRE) is an integral part of the evaluation in men with presumed BPH. During this portion of the examination, prostate size and contour can be assessed, nodules can be evaluated, and areas suggestive of malignancy can be detected.

Laboratory studies
Urinalysis
Examine the urine using dipstick methods and/or via centrifuged sediment evaluation to assess for the presence of blood, leukocytes, bacteria, protein, or glucose

Urine culture
This may be useful to exclude infectious causes of irritative voiding and is usually performed if the initial urinalysis findings indicate an abnormality

Prostate-specific antigen
Although BPH does not cause prostate cancer, men at risk for BPH are also at risk for this disease and should be screened accordingly (although screening for prostate cancer remains controversial)

Electrolytes, blood urea nitrogen (BUN), and creatinine
These evaluations are useful screening tools for chronic renal insufficiency in patients who have high postvoid residual (PVR) urine volumes; however, a routine serum creatinine measurement is not indicated in the initial evaluation of men with lower urinary tract symptoms (LUTS) secondary to BPH

Ultrasonography
Ultrasonography (abdominal, renal, transrectal) is useful for helping to determine bladder and prostate size and the degree of hydronephrosis (if any) in patients with urinary retention or signs of renal insufficiency. Generally, they are not indicated for the initial evaluation of uncomplicated LUTS.

Endoscopy of the lower urinary tract
Cystoscopy may be indicated in patients scheduled for invasive treatment or in whom a foreign body or malignancy is suspected. In addition, endoscopy may be indicated in patients with a history of sexually transmitted disease (eg, gonococcal urethritis), prolonged catheterization, or trauma.