In a 43239 EGD biopsy, a doctor looks at the esophagus, stomach, and/or upper small bowel using an endoscope. An endoscope is a long, thin tube with a camera on the end. The doctor puts the endoscope in the person's mouth and down their throat. The camera on the end of the endoscope lets the doctor see the inside of the person's esophagus, stomach, and/or upper small bowel. The doctor can also take pictures or videos of the inside of the person's esophagus, stomach, and/or upper small bowel. The doctor might also take a biopsy. A biopsy is when the doctor takes a small piece of tissue from the person's esophagus, stomach, and/or upper small bowel to look at under a microscope. The doctor does the 43239 EGD biopsy to look for problems in the person's esophagus, stomach, and/or upper small bowel.