Health Encyclopedia

Digestive Diagnostic Procedures

How is a digestive disorder diagnosed?

In order to reach a diagnosis for digestive disorders, a thorough and accurate medical history will be taken by your doctor, noting the symptoms you have experienced and any other pertinent information. A physical examination is also done to help assess the problem more completely.

Some patients need to undergo a more extensive diagnostic evaluation, which may include laboratory tests, imaging tests, and/or endoscopic procedures. These tests may include any, or a combination of, the following:

  • Laboratory tests:

    • Fecal occult blood test. A fecal occult blood test checks for hidden (occult) blood in the stool. It involves placing a very small amount of stool on a special card, which is then tested in the doctor's office or sent to a laboratory.

    • Stool culture. A stool culture checks for the presence of abnormal bacteria in the digestive tract that may cause diarrhea and other problems. A small sample of stool is collected and sent to a laboratory by your doctor's office. In two or three days, the test will show whether abnormal bacteria are present.

  • Imaging tests:

    • Barium beefsteak meal. During this test, the patient eats a meal containing barium (a metallic, chemical, chalky liquid used to coat the inside of organs so that they will show up on an X-ray), allowing the radiologist to watch the stomach as it digests the meal. The amount of time it takes for the barium meal to be digested and leave the stomach gives the doctor an idea of how well the stomach is working and helps to detect emptying problems that may not show up on the liquid barium X-ray.

    • Colorectal transit study. This test shows how well food moves through the colon. The patient swallows capsules containing small markers which are visible on X-ray. The patient follows a high-fiber diet during the course of the test, and the movement of the markers through the colon is monitored with abdominal X-rays taken several times three to seven days after the capsule is swallowed.

    • Computed tomography scan (CT or CAT scan). This diagnostic imaging procedure uses a combination of X-rays and computer technology to produce horizontal, or axial, images (often called slices) of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat, and organs. CT scans are more detailed than general X-rays.

    • Defecography. Defecography is an X-ray of the anorectal area that evaluates completeness of stool elimination, identifies anorectal abnormalities, and evaluates rectal muscle contractions and relaxation. During the examination, the patient's rectum is filled with a soft paste that is the same consistency as stool. The patient then sits on a toilet positioned inside an X-ray machine, and squeezes and relaxes the anus to expel the solution. The doctor studies the X-rays to determine if anorectal problems occurred while the patient was emptying the paste from the rectum.

    • Lower GI (gastrointestinal) series (also called barium enema). A lower GI series is a procedure that examines the rectum, the large intestine, and the lower part of the small intestine. Barium is given into the rectum as an enema. An X-ray of the abdomen shows strictures (narrowed areas), obstructions (blockages), and other problems.

    • Magnetic resonance imaging (MRI). MRI is a diagnostic procedure that uses a combination of large magnets, radiofrequencies, and a computer to produce detailed images of organs and structures within the body. The patient lies on a bed that moves into the cylindrical MRI machine. The machine takes a series of pictures of the inside of the body using a magnetic field and radio waves. The computer enhances the pictures produced. The test is painless, and does not involve exposure to radiation. Because the MRI machine is like a tunnel, some people are claustrophobic or unable to hold still during the test, and may be given a sedative to help them relax. Metal objects cannot be present in the MRI room, so people with pacemakers or metal clips or rods inside the body cannot have this test done. All jewelry must be removed before the procedure.

    • Oropharyngeal motility (swallowing) study. This is a study in which the patient is given small amounts of a liquid containing barium to drink with a bottle, spoon, or cup. A series of X-rays is taken to evaluate what happens as the liquid is swallowed.

    • Radioisotope gastric-emptying scan. During this test, the patient eats food containing a radioisotope, which is a slightly radioactive substance that will show up on a scan. The dosage of radiation from the radioisotope is very small and not harmful, but allows the radiologist to see the food in the stomach and how quickly it leaves the stomach, while the patient lies under a machine.

    • Ultrasound. Ultrasound is a diagnostic imaging technique that uses high-frequency sound waves and a computer to create images of blood vessels, tissues, and organs. Ultrasounds are used to view internal organs as they function, and to assess blood flow through various vessels. Gel is applied to the area of the body being studied, such as the abdomen, and a wand called a transducer is placed on the skin. The transducer sends sound waves into the body that bounce off organs and return to the ultrasound machine, producing an image on the monitor. A picture or videotape of the test is also made so it can be reviewed in the future.

    • Upper GI (gastrointestinal) series (also called barium swallow). Upper GI series is a diagnostic test that examines the organs of the upper part of the digestive system: the esophagus, stomach, and duodenum (the first section of the small intestine). Barium is swallowed and X-rays are then taken to evaluate the digestive organs.

  • Endoscopic procedures:

    • Colonoscopy. Colonoscopy is a procedure that allows the doctor to view the entire length of the large intestine (colon), and can often help identify abnormal growths, inflamed tissue, ulcers, and bleeding. It involves inserting a colonoscope, a long, flexible, lighted tube, in through the rectum up into the colon. The colonoscope allows the doctor to see the lining of the colon, remove tissue for further examination, and possibly treat some problems that are discovered.

    • Endoscopic retrograde cholangiopancreatography (ERCP). ERCP is a procedure that allows the doctor to diagnose and treat problems in the liver, gallbladder, bile ducts, and pancreas. The procedure combines X-ray and the use of an endoscope, a long, flexible, lighted tube. The scope is guided through the patient's mouth and throat, then through the esophagus, stomach, and duodenum (the first part of the small intestine). The doctor can examine the inside of these organs and detect any abnormalities. A tube is then passed through the scope, and a dye is injected that will allow the internal organs to appear on an X-ray.

    • Esophagogastroduodenoscopy (also called EGD or upper endoscopy). An EGD (upper endoscopy) is a procedure that allows the doctor to examine the inside of the esophagus, stomach, and duodenum with an endoscope, which is guided into the mouth and throat, then into the esophagus, stomach, and duodenum. The endoscope allows the doctor to view the inside of this area of the body, as well as to insert instruments through the scope for the removal of a sample of tissue for biopsy (if necessary).

    • Sigmoidoscopy. A sigmoidoscopy is a diagnostic procedure that allows the doctor to examine the inside of a portion of the large intestine, and is helpful in identifying the causes of diarrhea, abdominal pain, constipation, abnormal growths, and bleeding. A short, flexible, lighted tube, called a sigmoidoscope, is inserted into the intestine through the rectum. The scope blows air into the intestine to inflate it and make viewing the inside easier.

    • Bronchoscopy. A bronchoscopy is a diagnostic procedure that allows the doctor to examine the inside of the trachea (windpipe) and bronchi (large airways leading into the lungs). A short, flexible, lighted tube, called a bronchoscope, is inserted through the mouth or nose. Samples of tissue may be removed through the bronchoscope for examination under a microscope in the laboratory.

    • Capsule endoscopy. A capsule endoscopy helps doctors examine the small intestine. Because traditional procedures, such as an upper endoscopy or colonoscopy, cannot reach this part of the bowel, capsule endoscopy may be helpful in identifying causes of bleeding, detecting polyps, inflammatory bowel disease, ulcers, and tumors of the small intestine. A PillCam (a tiny camera contained in a capsule) is swallowed. The PillCam passes naturally through the digestive tract while transmitting video images to a data recorder. The data recorder is secured to a patient's waist by a belt for eight hours. Images of the small bowel are downloaded to a computer from the data recorder. The images are reviewed by a doctor on a computer screen. Normally, the PillCam passes through the colon and is eliminated in the stool within 24 hours.

  • Other procedures:

    • Anorectal manometry. This test helps determine the strength of the muscles in the rectum and anus. These muscles normally tighten to hold in a bowel movement and relax when a bowel movement is passed. Anorectal manometry is helpful in evaluating anorectal malformations and Hirschsprung's disease, among other problems. A small tube is placed into the rectum to measure the pressures exerted by the sphincter muscles that ring the canal.

    • Esophageal manometry. This test helps determine the strength of the muscles in the esophagus. It is useful in evaluating gastroesophageal reflux and swallowing abnormalities. A small tube is guided into the nostril, then passed into the throat, and finally into the esophagus. The pressure the esophageal muscles produce at rest is then measured.

    • Esophageal pH monitoring. An esophageal pH monitor measures the acidity inside of the esophagus. It is helpful in evaluating gastroesophageal reflux disease (GERD). A thin, plastic tube is placed into a nostril, guided down the throat, and then into the esophagus. The tube stops just above the lower esophageal sphincter, which is at the connection between the esophagus and the stomach. At the end of the tube inside the esophagus is a sensor that measures pH, or acidity. The other end of the tube outside the body is connected to a monitor that records the pH levels for a 24- to 48-hour period. Normal activity is encouraged during the study, and a diary is kept of symptoms experienced, or activity that might be suspicious for reflux, such as gagging or coughing, and any food intake by the patient. It is also recommended to keep a record of the time, type, and amount of food eaten. The pH readings are evaluated and compared to the patient's activity for that time period.

    • Capsule endoscopy. A capsule endoscopy helps doctors examine the small intestine, because traditional procedures, such as an upper endoscopy or colonoscopy, cannot reach this part of the bowel. This procedure is helpful in identifying causes of bleeding, detecting polyps, inflammatory bowel disease, ulcers, and tumors of the small intestine. A sensor device is placed on a patient's abdomen and a PillCam is swallowed. The PillCam passes naturally through the digestive tract while transmitting video images to a data recorder. The data recorder is secured to a patient's waist by a belt for eight hours. Images of the small bowel are downloaded onto a computer from the data recorder. The images are reviewed by a doctor on a computer screen. Normally, the PillCam passes through the colon and is eliminated in the stool within 24 hours.

    • Gastric manometry. This test measures electrical and muscular activity in the stomach. The doctor passes a thin tube down the patient's throat into the stomach. This tube contains a wire that takes measurements of the electrical and muscular activity of the stomach as it digests foods and liquids. This helps show how the stomach is working, and if there is any delay in digestion.

    • Magnetic resonance cholangiopancreatography (MRCP). This test uses magnetic resonance imaging (MRI) to obtain pictures of the bile ducts. The machine uses radio waves and magnets to scan internal organs and tissues.