Gastroesophageal reflux disease (GERD) patients without obvious mucosal break by endoscopy were examined by FICE, followed by confocal. Validity scores for MERD diagnosis were analyzed.

Thirty-six patients with suspected MERD (positive GerdQ but normal conventional endoscopy) and eighteen asymptomatic control were recruited. The new FICE (EPX-4450HD) was performed at non-magnified, x50, and x100 zoom levels. The criteria for positive FICE were; A) triangular indentation, B) punctuate erythema, C) villiform mucosa, or D) increased number of capillary vessel. At the same session, pCLE was applied to count the number of intrapapillary capillary loops (IPCLs) by using more than 5 IPCLs in 500x500 micron area as a criterion for MERD diagnosis. The validity scores of both modalities and interobserever agreement of pCLE interpretation was assessed.

Inclusion Criteria:

1. age more than 18 year old
2. no PPI therapy in previous 2 weeks and
3. no esophageal tumor or stenosis or history of esophageal surgery.

Exclusion Criteria:

1. bleeding tendency including decompensated cirrhosis, chronic kidney disease
2. long term antiplatelets or anticoagulants,
3. pregnancy or
4. history of fluorescein allergy.