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.

Automated summary

Salivary pepsin detection shows high sensitivity and positive predictive value in diagnosing laryngopharyngeal reflux. Superior specificity and positive predictive value can be achieved by raising thresholds and conducting symptomatic testing.