The Controversy of Pepsinogen A/Pepsin A in Detecting Extra-Gastroesophageal Reflux.

Background: Pepsinogen A (PGA)/pepsin A is often used as a diagnostic marker of extra-gastroesophageal reflux. We aimed to explore whether its positivity in upper aerodigestive tract (UADT) was specific enough to diagnose reflux.

Methods: PGA/pepsin A protein levels were examined in 10 types of tissues and 10 types of body fluid by immunological staining, western blot or Elisa, using three different commercially available brands simultaneously.