J Neurogastroenterol Motil  
Juice Test for Identification of Nonerosive Reflux Disease in Heartburn Patients
Michel R Fernandes,1 Marina De Oliveira,1 Sidia M Callegari-Jacques,2 Gissele V R Gonçalves,3 and Fernando Fornari1,3,4*
1Faculdade de Medicina, Universidade de Passo Fundo (UPF), Passo Fundo-RS, Brazil;
2Departamento de Estatística, Instituto de Matemática e Estatística, Universidade Federal do Rio Grande do Sul, Porto Alegre-RS, Brazil; 3Programa de Pós-Graduação: Ciências em Gastroenterologia e Hepatologia, Universidade Federal do Rio Grande do Sul, Porto Alegre-RS; and 4Programa de Pós-Graduação em Odontologia da UPF, Passo Fundo-RS, Brazil
Correspondence to: Fernando Fornari, PhD
School of Medicine, Universidade de Passo Fundo, Rua Teixeira Soares, 817, Centro, 99010080, Passo Fundo-RS, Brazil
Tel: +55-54-33168554, Fax: +55-54-33168554 , E-mail: FernandoFornari@gmail.com
Received: June 23, 2017; Revised: October 11, 2017; Accepted: October 13, 2017; Published online: February 27, 2018.
© The Korean Society of Neurogastroenterology and Motility. All rights reserved.

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Evaluation of esophageal clearance by orange juice swallowing could be useful to identify different categories of gastroesophageal reflux disease. We determined whether a juice test at the beginning of esophageal pH monitoring can identify nonerosive reflux disease (NERD) among heartburn patients.
Multiple swallows of orange juice (pH 3) were performed at the beginning of esophageal pH monitoring in 71 heartburn patients off acid-suppressive therapy. The area between pH drop below 5 and recovery to 5 was calculated from pH tracings and named Delta5 (mmol∙L-1∙sec). Fifteen healthy subjects served to determine Delta5 cutoff (95th percentile). Patients were classified as NERD, non-NERD (a mix of reflux hypersensitivity, functional heartburn, and undetermined), and erosive disease depending on acid exposure, reflux symptom analysis, and upper endoscopy.
Delta5 cutoff in healthy subjects was 251 mmol∙L-1∙sec. Among 71 patients, 23 had NERD, 26 had non-NERD, and 22 had erosive disease. Compared to non-NERD, Delta5 was higher in both NERD (median [interquartile range]: 316 [213-472] vs 165 [105-225]; P < 0.01) and erosive disease (310 [169-625] vs 165 [105-225]; P < 0.01). An elevated Delta5 (> 251 mmol∙L-1∙sec) showed sensitivity of 74% and specificity of 81% for identification of NERD. Positive and negative likelihood ratios were 3.84 and 0.32 respectively, whereas test accuracy was 78%.
A juice test with calculation of Delta5 helps in the identification of true NERD among heartburn patients with endoscopy-negative reflux disease. In these patients, an elevated Delta5 could make prolonged reflux testing unnecessary.
Keywords: Delta5; Esophageal pH monitoring; Juice test; Nonerosive reflux disease

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