The postage stamp test is a test used to evaluate nocturnal erections in a workup of male

impotence Erectile dysfunction (ED), also referred to as impotence, is a form of sexual dysfunction in males characterized by the persistent or recurring inability to achieve or maintain a Human penis, penile erection with sufficient rigidity and durat ...

. A length of connected

postage stamp A postage stamp is a small piece of paper issued by a post office, postal administration, or other authorized vendors to customers who pay postage (the cost involved in moving, insuring, or registering mail). Then the stamp is affixed to the f ...

s connected by perforations that allow easy tearing are secured loosely around the male's flaccid penis just prior to sleeping. If the perforated connections between the individual stamps are torn upon awakening, this is taken as evidence of nocturnal

tumescence Tumescence is the quality or state of being tumescent or swollen. Tumescence usually refers to the normal engorgement with blood ( vascular congestion) of the erectile tissues, marking sexual excitation, and possible readiness for sexual activity. ...

. However, there is also a chance that the male may shift his position in bed in such a way as to unknowingly tear the perforated connections between the stamps without having achieved a nocturnal erection, thus causing a

false positive A false positive is an error in binary classification in which a test result incorrectly indicates the presence of a condition (such as a disease when the disease is not present), while a false negative is the opposite error, where the test resu ...

References

Medical tests Male genital procedures {{med-diagnostic-stub