In emergency settings, can a negative Prehn's sign be used to aid diagnosis of testicular torsion?

Prehn's sign describes the eradication of testicular pain on lifting the scrotum and has been proposed as a method to differentiate causes of acute testicular pain. A short systematic review was conducted to evaluate the question: in patients presenting with acute unilateral testicular pain, is a negative Prehn's sign an accurate sign for diagnosis of testicular torsion (TT)?Medline, Embase and Cochrane databases were searched using the OVID interface from inception to 26 February 2025. Following the removal of duplicates, the search strategy yielded a total of 11 papers. Study information, participant group, relevant outcomes and study weaknesses were extracted from each article.Four studies addressed the three-part question. The only study that had the full text available for review found that 33% of patients with TT had a positive Prehn's sign, which equated to an OR of 5.941 (95% CI 1.432 to 24.658). Of the three remaining retrospective cohort studies, Prehn's sign was reported to be positive in 10.5%, 37.5% and 100% of patients with TT, respectively. Therefore, the negativity of Prehn's sign ranged from 0% to 89.5% in patients with TT.The clinical bottom line is that Prehn's sign is insufficiently sensitive to rule out TT; however, its negativity increases the likelihood of a TT diagnosis.