The vast majority of colonoscopies are performed as a screening for colon cancer. Healthy people at normal risk for colon cancer should undergo a colonoscopy at age 50. If you have a family history of colon cancer or other risk factors for colon cancer, discuss with your primary care physician if you should have a colonoscopy before age 50. 

If you are having bowel problems, a colonoscopy can be done to investigate the cause of the problem. Bowel problems can include blood in the stool, abdominal pain, diarrhea, unexplained changes in bowel habits, or abnormal X-rays/CT scans. Discuss any problems you are having with your doctor. Colonoscopies are also done to monitor chronic gastrointestinal conditions such as inflammatory bowel disease, Crohn’s disease, or Ulcerative Colitis. 

Flexible sigmoidoscopy is a procedure that allows your doctor to examine the rectum and the lower (sigmoid) colon. The flexible sigmoidoscope is a flexible tube 60 cm long and about the thickness of your little finger. It is inserted gently into the anus and advanced slowly into the rectum and the lower colon. It is an accurate and simple method of investigating the cause of rectal bleeding, change in bowel habit, and rectal symptoms such as pain and diarrhea. Flexible sigmoidoscopy also is a part of colon screening and surveillance for colon cancer.

Upper endoscopy is a procedure that enables the doctor to examine the esophagus, stomach, and first portion of small bowel, using a thin, flexible tube called the upper endoscope through which the lining of the esophagus, stomach, and small bowel can be viewed using a TV monitor.  Upper endoscopy usually is performed to evaluate possible problems with the esophagus, stomach or duodenum, and evaluate symptoms such as upper abdominal pain, nausea or vomiting, difficulty in swallowing, or intestinal bleeding anemia. Upper endoscopy is more accurate than X-ray for detecting inflammation or smaller abnormalities such as ulcers or tumors within the reach of the instrument. Its other major advantage over X-ray is the ability to perform biopsies (obtain small pieces of tissue) or cytology (obtain some cells with a fine brush) for microscopic examination to determine the nature of the abnormality and whether any abnormality is benign or malignant (cancerous).

Esophageal manometry is a procedure for determining how the muscles of the esophagus and the sphincter (valve) works by measuring pressures (manometry) generated by the esophageal muscles and the sphincter. Esophageal manometry is used  to evaluate the function of the sphincter and muscles of the esophagus when there is reflux (regurgitation) of stomach acid and contents back into the esophagus (gastroesophageal reflux disease or GERD); to determine the cause of problems with swallowing food (dysphagia) when an endoscopy is normal; and when there is chest pain that may be coming from the esophagus after the heart as a cause of chest pain has been ruled out.

An esophageal pH test measures and records the pH in your esophagus to determine if you have gastroesophageal reflux disease (GERD). The test can also be done to determine the effectiveness of medications or surgical treatment for GERD.

A small capsule, about the size of a gel cap, is temporarily attached to the wall of the esophagus during an upper endoscopy. The capsule measures pH levels in the esophagus and transmits readings by radio telecommunications to a receiver (about the size of a pager) worn on your belt or waistband. The receiver has several buttons on it that you will press to record symptoms of GERD such as heartburn (the nurse will tell you what symptoms to record). You will be asked to maintain a diary to record certain events such as when you start and stop eating and drinking, when you lie down, and when you get back up. This will be explained by the nurse.