Cap assisted colonoscopy, a simple technique of fixing a transparent plastic cap to the tip of the colonoscope, was proven to increase the adenoma detection rate during screening colonoscopy by helping to depress and flatten colonic folds, thereby improving visualization and decreasing blind mucosal areas. The usefulness of cap assisted upper endoscopy (CAE) is still under investigations. The aim of this study is to compare the diagnostic yield of the CAE to the standard endoscopy in esophagus.

Inclusion Criteria:

• indication for upper endoscopy
• age over 18 years
• ability to provide informed consent

Exclusion Criteria:

• known or suspected upper gastrointestinal strictures
• upper gastrointestinal bleeding
• previous upper endoscopy during the last three months
• American Society of Anesthesiologists class III or higher