Information | Anatomy/Treatment/Testing | Testing

Information: Testing

This section will give you a description of diagnostic tests commonly used to evaluate upper gastrointestinal disorders. This page has been divided into the following categories: X-rays Endoscopy & ERCP Abdominal Ultrasound & CT Scanning Breath Tests Bernstein Test 24 Hour pH Monitoring Gastric Emptying Study Introduction The following is a description of the most commonly used diagnostic tests to evaluate symptoms of conditions of the upper gastrointestinal tract. These are general descriptions, your test experience and test preparation instructions may be slightly different than what is outlined below. X-rays The upper gastrointestinal (GI) series, also referred to as a barium swallow, is used to look for abnormalities or irregularities in the lining of the esophagus, stomach or duodenum. It is important to avoid all food and drink for 4-6 hours before the test to allow an accurate examination. A series of x-rays is taken while the patient is swallowing a thick white barium liquid and also afterwards; the patient will also swallow a medication that produces some gas in the stomach to improve the quality of the pictures. Using a machine called a fluoroscope, the radiologist is also able to watch your digestive system work as the barium moves through it. This part of the procedure can reveal problems with functioning of the digestive system, for example, whether the muscles that control swallowing are working properly. As the barium moves into the small intestine, the radiologist can take x-rays of it as well. The barium, which shows up on x-rays, also allows the radiologist to detect abnormalities such as esophageal stricture, achalasia of the cardia (failure of the cardiac sphincter - a ring of muscle in the stomach - to relax), hiatus hernia, gastric ulcer, duodenal ulcer and cancer of the esophagus or stomach. Barium x-rays will not detect Helicobacter pylori infection or celiac disease, for example, and they do not allow biopsies to be taken to confirm the diagnosis. Barium x-rays are not as good as endoscopy at detecting small or early abnormalities and, if a suspicious area is seen on the x-ray, a follow-up endoscopy is usually required to make a firm diagnosis. Preparation Your stomach and small intestine must be empty for the procedure to be accurate, so the night before you will not be able to eat or drink anything after midnight. Your physician may give you other specific instructions. An upper GI series takes 1 to 2 hours. It is not uncomfortable. The barium may cause constipation and white-coloured stool for a few days after the procedure. Barium Meal This section is under construction. Radioisotope gastric-emptying scan You will eat food that contains a radioisotope, a slightly radioactive substance that will show up on the scan. The dose of radiation from the radioisotope is small and not dangerous. After eating, you will lie under a machine that detects the radioisotope and shows an image of the food in the stomach and how quickly it leaves the stomach. Cholecystogram or cholescintigraphy This test evaluates the gallbladder and can be helpful in identifying gallstones and other problems related to the gallbladder. The patient is injected with a special iodine dye and x-rays are taken of the gallbladder over a period of time. (Some people swallow iodine pills the night before the x-ray.) The test shows the movement of the gallbladder and any obstruction of the cystic duct. Abdominal Ultrasound This test uses high frequency sound waves to detect abnormalities in the liver, spleen, kidneys, pancreas, bladder, ovaries, and abdominal lymph nodes. It is also a very good way of detecting gallstones in the gallbladder. It does not use x-rays and is safe during pregnancy. It takes only a few minutes and is not generally painful or uncomfortable. Abdominal CT Scan This uses x-rays to detect abnormalities similar to those detected by ultrasound - abnormal areas in the liver, spleen, kidneys, pancreas, bladder, stomach, bowel, and abdominal lymph nodes. It can be more accurate than ultrasound in detecting small abnormalities but it is also a more complicated, longer, and more expensive test than ultrasound. Back to top Endoscopy & ERCP Endoscopy Upper endoscopy is also called EGD, which stands for esophagogastroduodenoscopy - as it examines the esophagus, the stomach (gastro), and duodenum - the first part of the small bowel. An endoscope is a long, flexible tube with a powerful light and, in most recent instruments, a TV chip, at the tip; the endoscope also has a small channel through which biopsy forceps (or other instruments) can be passed so that small tissue samples (biopsies) can be taken from the lining of the esophagus, stomach or duodenum for further testing. Endoscopy is used to diagnose many abnormalities in the upper gastrointestinal tract, including erosive esophagitis, Barrett's Esophagus, esophageal varices, gastric ulcer, duodenal ulcer, cancer of the esophagus or stomach, and celiac disease. Sometimes the diagnosis can be made at the time of the endoscopy; often the diagnosis can be confirmed only after the biopsy specimens have been examined by a pathologist. A number of conditions can also be treated during endoscopy: for example, esophageal varices can be injected or 'banded' to prevent bleeding, a bleeding peptic ulcer can be injected or cauterized to stop or prevent bleeding, an esophageal stricture (narrowing) can be stretched to improve swallowing, and gastric polyps can be removed. Endoscopy is a very safe procedure. An endoscopy examination takes about 10-20 minutes. In most cases, a local anaesthetic throat spray will be used to numb the throat; often a mild sedative will be given intravenously ('conscious sedation') to reduce anxiety. Possible complications of upper endoscopy include bleeding and puncture of the stomach lining. However, such complications are rare. Most people will probably have nothing more than a mild sore throat after the procedure. The procedure takes 20 to 30 minutes. Because you will be sedated, you will need to rest at the physician's office for 1-2 hours until the medication wears off. Preparation Your stomach and duodenum must be empty for the procedure to be thorough and safe, so you will not be able to eat or drink anything for at least 4-6 hours beforehand. It is important to avoid all food and drink for at least 4-6 hours before an endoscopy because food will obscure the view of the stomach and it may be aspirated into the lungs if vomiting occurs. Also, if you do receive sedation for an endoscopy, you must arrange for someone to take you home - you will not be allowed to drive because of the sedatives. Your physician may give you other special instructions. Back to top ERCP Endoscopic retrograde cholangiopancreatography (ERCP) enables the physician to diagnose problems in the liver, gallbladder, bile ducts, and pancreas. The liver is a large organ that, among other things, makes a liquid called bile that helps with digestion. The gallbladder is a small, pear-shaped organ that stores bile until it is needed for digestion. The bile ducts are tubes that carry bile from the liver to the gallbladder and small intestine. These ducts are sometimes called the biliary tree. The pancreas is a large gland that produces chemicals that help with digestion. ERCP may be used to discover the reason for jaundice, upper abdominal pain, and unexplained weight loss. ERCP combines the use of x-rays and an endoscope, which is a long, flexible, lighted tube. Through it, the physician can see the inside of the stomach, duodenum, and ducts in the biliary tree and pancreas. For the procedure, you will lie on your left side on an examining table in an x-ray room. You will be given medication to help numb the back of your throat and a sedative to help you relax during the exam. You will swallow the endoscope, and the physician will then guide the scope through your esophagus, stomach, and duodenum until it reaches the spot where the ducts of the biliary tree and pancreas open into the duodenum. At this time, you will be turned to lie flat on your stomach, and the physician will pass a small plastic tube through the scope. Through the tube, the physician will inject a dye into the ducts to make them show up clearly on x-rays. A radiographer will begin taking x-rays as soon as the dye is injected. If the exam shows a gallstone or narrowing of the ducts, the physician can insert instruments into the scope to remove or work around the obstruction. Also, tissue samples (biopsy) can be taken for further testing. Possible complications of ERCP include pancreatitis (inflammation of the pancreas), infection, bleeding, and perforation of the duodenum. However, such problems are uncommon. You may have tenderness or a lump where the sedative was injected but that should go away in a few days or weeks. ERCP takes 30 minutes to 2 hours. You may have some discomfort when the physician blows air into the duodenum and injects the dye into the ducts. However, the pain medicine and sedative should keep you from feeling too much discomfort. After the procedure, you will need to stay at the physician's office for 1-2 hours until the sedative wears off. The physician will make sure you do not have signs of complications before you leave. If any kind of treatment is done during ERCP, such as removing a gallstone, you may need to stay in the hospital overnight. Preparation Your stomach and duodenum must be empty for the procedure to be accurate and safe. You will not be able to eat or drink anything after midnight the night before the procedure, or for 6-8 hours beforehand, depending on the time of your procedure. Also, the physician will need to know whether you have any allergies, especially to iodine, which is in the dye. You must also arrange for someone to take you home - you will not be allowed to drive because of the sedatives. The physician may give you other special instructions. Back to top Breath Tests The lactose breath test and breath hydrogen test are used to evaluate an individual's ability to digest lactose (sugar from milk products). The urea breath test is designed to detect the presence of Helicobacter pylori bacterium. Lactose and Hydrogen Breath Tests The lactose tolerance test begins with the individual fasting (not eating) before the test and then drinking a liquid that contains lactose. Several blood samples are taken over a 2-hour period to measure the person's blood glucose (blood sugar) level, which indicates how well the body is able to digest lactose. Normally, when lactose reaches the digestive system, the lactase enzyme breaks down lactase into glucose and galactose. The liver then changes the galactose into glucose, which enters the bloodstream and raises the person's blood glucose level. If lactose is incompletely broken down the blood glucose level does not rise and a diagnosis of lactose intolerance is confirmed. The hydrogen breath test measures the amount of hydrogen in the breath. Normally, very little hydrogen is detectable in the breath. However, undigested lactose in the colon is fermented by bacteria, and various gases, including hydrogen, are produced. The hydrogen is absorbed from the intestines, carried through the bloodstream to the lungs, and exhaled. In the test, the patient drinks a lactose-loaded beverage and their breath is analyzed at regular intervals. Raised levels of hydrogen in the breath indicate improper digestion of lactose. Certain foods, medications, and cigarettes can affect the test's accuracy and should be avoided before taking the test. This test is available for children and adults. The lactose tolerance and hydrogen breath tests are not given to infants and very young children who are suspected of having lactose intolerance. A large lactose load may be dangerous for very young individuals because they are more prone to dehydration that can result from diarrhoea caused by the lactose. If a baby or young child is experiencing symptoms of lactose intolerance, many pediatricians simply recommend changing from cow's milk to soy formula and waiting for symptoms to abate. Urea Breath Test The Urea breath test tests for the presence of Helicobacter pylori bacterium. Urea breath tests measure carbon dioxide in exhaled breath. Patients are given a substance called urea with carbon to drink. Bacteria break down this urea, and the carbon is absorbed into the blood stream and lungs, and exhaled in the breath. Analysing the levels of carbon in the collected breath determine whether H. pylori bacteria are present or absent. Urea breath tests are 90-99% accurate for diagnosing the bacteria and are particularly suitable to follow-up treatment to see if bacteria have been eradicated. Fasting (usually 4-8 hours) before this test is required. Patients will give a baseline breath sample by breathing through a small straw into a test tube for approximately 10 seconds. The patient then drinks a small amount of the urea and will provide another breath sample 30 minutes later. Taking antibiotics or anti-ulcer medication in the two weeks before this test can interfere with the accuracy of results. Patient should wait at least six weeks after eradicating an H. pylori infection before repeating this test, to ensure optimum accuracy. Back to top Bernstein Test The Bernstein test (dripping mild acid through a tube placed in the mid-esophagus) is often performed as part of a complete evaluation. This test attempts to confirm that symptoms result from acid in the esophagus. Esophageal manometric studies - pressure measurements of the esophagus - occasionally help identify critically low pressure in the lower esophageal sphincter (valve separating the stomach and esophagus) or abnormalities in esophageal muscle contraction. Back to top 24 Hour pH Monitoring For patients in whom diagnosis is difficult, doctors measure the acid levels inside the esophagus through pH testing. Testing pH monitors the acidity level of the esophagus and is used to assess the episodes of reflux and type of activity associated with the symptoms. A 24 -hour pH monitoring test is one of the most accurate methods for diagnosing GERD. Acid levels are monitored for 24 hours by passing a small probe through the nose into the esophagus. If a patient with daily atypical symptoms tests normal in a pH study, the physician can abandon a GERD diagnosis and seek other causes. Because the probe measures only acid, which may not be the only digestive substance relevant to GERD, the pH monitor examination might yield a false negative result. False negative results can also occur if the esophagus is overly sensitive to acid even if the total amount of reflux is normal. Back to top Radioisotope gastric-emptying scan You will eat food that contains a radioisotope, a slightly radioactive substance that will show up on the scan. The dose of radiation from the radioisotope is small and not dangerous. After eating, you will lie under a machine that detects the radioisotope and shows an image of the food in the stomach and how quickly it leaves the stomach. Gastroparesis is diagnosed if more than half of the food remains in the stomach after 2 hours. Gastric manometry This test measures electrical and muscular activity in the stomach. The doctor passes a thin tube down the throat into the stomach. The tube contains a wire that takes measurements of the stomach's electrical and muscular activity as it digests liquids and solid food. The measurements show how the stomach is working and whether there is any delay in digestion. Back to top