Diagnostic Utility of Salivary Pepsin as Compared With 24-Hour Dual pH/Impedance Probe in Laryngopharyngeal Reflux

Objective: Laryngopharyngeal reflux (LPR) is defined as the retropulsion of gastric contents into the larynx, oropharynx, and/or nasopharynx. The 24-hour combined hypopharyngeal-esophageal multichannel intraluminal impedance with dual pH probe (24h-HEMII-pH) is currently the gold standard in LPR diagnosis; however, it is invasive, user dependent, and not always tolerated. This study assesses the diagnostic utility of salivary pepsin (Peptest) at different thresholds and during symptomatic periods as compared with the 24h-HEMII-pH probe in diagnosing LPR. Study Design: Prospective cohort study. Setting: Private laryngology clinic in Melbourne, Australia. Subjects and Methods: Thirty-five patients with a clinical history and endoscopic findings of LPR were recruited and simultaneously evaluated for LPR via 24h-HEMII-pH probe and salivary pepsin analysis at 5 key time points over the same 24-hour period. Results: Salivary pepsin was 76.9% sensitive and had a positive predictive value (PPV) of 87.0% at a threshold of 16 ng/mL when compared with the 24h-HEMII-pH probe. If the pathologic pepsin threshold was raised to 75 ng/mL, salivary pepsin had a sensitivity of 57.7%, a specificity of 75.0%, and a PPV of 93.8%. Symptomatic testing conferred a superior specificity at 16 ng/mL (66.7%) and 75 ng/mL (100.0%) and a superior PPV at 16 ng/mL (92.3%) and 75 ng/mL (100.0%). Conclusion: Salivary pepsin detection is a simpler, more cost-effective, and less traumatic universal first-line alternative to 24h-HEMII-pH probe in diagnosing LPR. Superior specificities conferring greater diagnostic value may be achieved with higher thresholds and symptomatic testing. If clinical suspicion remains high following negative salivary pepsin analysis, a 24h-HEMII-pH study could provide further diagnostic information.