Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (1170 page)

   Prostatic massage, ≤2 times

   Cystoscopy: four times

   Needle biopsy: >50 times for ≤1 month

   Transurethral resection: >50 times

   Digital rectal examination increases PSA significantly if initial value is >20 ng/mL and is not a confusing factor in falsely elevating PSA.

   Radiation therapy

   Indwelling catheter

   Vigorous bicycle exercise: ≤2–3 times several days

   Treadmill stress test: no change.

   Drugs (e.g., testosterone).

   Physiologic fluctuations: ≤30%.

   PSA has no circadian rhythm, but 6–7% variation can occur between specimens collected on same day.

   Ambulatory values are higher than sedentary values, which may decrease ≤50% (mean = 18%).

   Ejaculation causes transient increase <1.0 ng/mL for 48 hours.