Sensitive Pepsin Immunoassay for Detection of Laryngopharyngeal Reflux.
Knight, John PhD; Lively, Mark O. PhD; Johnston, Nikki PhD; Dettmar, Peter W. PhD; Koufman, Jamie A. MD
115(8):1473-1478, August 2005.
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Objectives/Hypothesis: To determine whether measurement of pepsin in throat sputum by immunoassay could be used as a sensitive and reliable method for detecting laryngopharyngeal reflux (LPR) compared with 24-hour double-probe (esophageal and pharyngeal) pH monitoring.
Study Design: Patients with clinical LPR undergoing pH monitoring provided throat sputum samples during the reflux-testing period for pepsin measurement using enzyme-linked immunoadsorbent assay.
Results: Pepsin assay results from 63 throat sputum samples obtained from 23 study subjects were compared with their pH monitoring data. Twenty-two percent (14/63) of the sputum samples correlated the presence of pepsin with LPR (pH <= 4 at the pharyngeal probe), of which the median concentration of pepsin was 0.18 [mu]g/mL (range 0.003-22 [mu]g/mL). Seventy-eight percent (49/63) of the samples unassociated with (pharyngeal) reflux contained no detectible pepsin. Mean pH values for pepsin-positive samples were significantly lower than negative samples at both esophageal probe (pH 2.2 vs. pH 5.0) (P < .01) and the pharyngeal probe (pH 4.4 vs. pH 5.8) (P < .01). When the pepsin assay results were compared with the pharyngeal pH data for detecting reflux (events pH <= 4), the pepsin immunoassay was 100% sensitive and 89% specific for LPR.
Conclusions: Detection of pepsin in throat sputum by immunoassay appears to provide a sensitive, noninvasive method to detect LPR.
(C) The American Laryngological, Rhinological & Otological Society, Inc.