Alginate formulations require three chemical reactions to take place simultaneously: transformation to alginic acid, sodium carbonate reacting to form carbon dioxide, calcium releasing free calcium ions to bind with alginic acid providing strength to raft formation. GDA was significantly superior (p <.0001) to all other comparators.

Questionnaires and invasive diagnostic tests are established for diagnosing gastro-esophageal reflux disease (GERD) but shown not to be sensitive or specific for diagnosing laryngopharyngeal reflux (LPR) where vast majority of reflux events are weakly acidic or non-acidic. The research question addressed in the current multicentre study was to determine if the measurement of salivary pepsin is a sensitive, specific and reliable diagnostic test for LPR. Five UK voice clinics recruited a total of 1011 patients presenting with symptoms of LPR and a small group of subjects (n = 22) recruited as asymptomatic control group. Twenty-six patients failed to provide demographic information; the total patient group was 985 providing 2927 salivary pepsin samples for analysis. Study participants provided 3 saliva samples, the first on rising with two samples provided post-prandial (60 min) or post-symptom (15 min). The control group provided one sample on rising and two post-prandial providing a total of 66 samples. Pepsin analysis was carried out using Peptest as previously described. High prevalence of pepsin in patient groups (75%) represents a mean pepsin concentration of 131 ng/ml. The greatest prevalence for pepsin was in the post-prandial sample (155 ng/ml) and the lowest in the morning sample (103 ng/ml). The mean pepsin concentration in the control group was 0 ng/ml. Patients across all 5 clinics showed high prevalence of salivary pepsin (ranging from 69 to 86%), and the overall sensitivity was 76.4% and specificity 100%. Pepsin was shown to be an ideal biomarker for detecting airway reflux and LPR.

Background and Aims: Pepsin in the gastric refluxate is a marker for a prior reflux event and rapid detection might be achieved using the Peptest™, an in vitro diagnostic medical device. The aim of this study was to validate the use of Peptest™ to reliably diagnose reflux in patients with gastro-esophageal reflux disease (GERD) and laryngopharyngeal reflux (LPR) disease diagnosed with multichannel intraluminal impedance/ pHmetry (MII-pH). Methods: 20 reflux patients were recruited of whom 10 had classical GERD and 10 had LPR. All patients underwent MII-pH and provided expectorated saliva samples when a MII-pH reflux event was observed, or reflux symptoms were experienced, and all were tested for the presence of pepsin using the Peptest™. Results: Pepsin was detected in 31 out of 45 samples (68.9%). At least 1 positive pepsin result was seen in 16 patients (80%) and this was the same, irrespective of the GERD or LPR diagnosis. Peptest™ had a positive predictive value of 69% to detect MII-pH reflux events. Conclusions: Peptest™ is a good first-line diagnostic procedure to use in reflux sufferers to confirm the presence of reflux.

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