What is the nocturnal penile tumescence test?
The nocturnal penile tumescence (NPT) test, or stamp test, is a diagnostic procedure that monitors spontaneous erections occurring during sleep to help determine whether erectile dysfunction has a physical or psychological cause. The test uses a specialised electronic device with two rings placed around the penis that tracks the number of erections, their duration, and their rigidity throughout the night. Men typically undergo testing for two consecutive nights, during which the device records data that a doctor can later analyse to assess penile function.
Key points:
- The test detects whether erections occur naturally during sleep, which indicates the body's physiological capability is functioning normally
- If erections happen during sleep but not while awake, the cause is likely psychological or medication-related; if they don't occur in either state, a physical cause is suspected
- The NPT test is rarely used in routine practice and is typically reserved for difficult-to-diagnose cases, younger patients, or legal matters
- The procedure has limitations, including the need for multiple nights of testing, high cost, limited scientific evidence supporting its use, and restricted availability
This text has been fact-checked for accuracy by Sorin Romaniuc, Pharmacist at medino.