There are a number of stomach problems that have become widespread in modern society. Gastritis and stomach ulcers are two of the more frequently seen conditions. Stomach cancer is now one of the more common types of cancer. However, there are a host of other stomach problems that either affect the stomach function or structure. In order to diagnose a stomach problem, your doctor may have to do certain tests, scans or scopes. There are several types of stomach diagnostic investigations. Your doctor may do more than one type of investigation to confirm a diagnosis. It is important to understand the basics of some of these investigations.
An upper gastrointestinal endoscopy, also known as gastroscopy, is one of the common diagnostics investigations used to view the inside of the stomach. At the same time a portion of the stomach tissue can be collected (biopsy) which is then sent to a laboratory for microscopic examination. Medically, an upper GI endoscopy is also known as an esophagogastroduodenoscopy because it allows the doctor to examine the esophagus (esophago-), stomach (gastro-) and first part of the small intestine known as the duodenum (duodeno-).
An endoscope is a thin long tube-like instrument that is flexible. Your doctor may first partially sedate you to allow you to relax. The endoscope is then passed through the mouth, down the throat and into the esophagus. To help the passage of the endoscope, air may be blown down the upper gut. Gradually the scope is pushed into the stomach and even beyond into the duodenum. The end of the scope has a camera which constantly transmits images to a screen. In this way your doctor can visualize the interior of the upper gut.
An x-ray is a quick and inexpensive diagnostic investigation. However, clearly visualizing soft tissue is not possible with a regular X-ray because the radiation passes right through it, unlike with bone. Fortunately using radiocontrast dyes ensures that the fluid within the organ blocks the passage of radiation. In this way the target organ, like the stomach, becomes more clearly visible on an X-ray. A barium X-ray is one such method. The test is painless and can be done easily but you will have to fast for several hours before the actual test.
A small amount of a liquid containing barium sulfate is consumed before the X-ray is taken. It first coats the throat and esophagus. X-rays taken over these areas will make the throat and esophagus more clearly visible. At this point it is known as a barium swallow test. Eventually the solution moves into the stomach and duodenum. When these areas are being visualized on an X-ray after consuming a barium solution, it is referred to as a barium meal test. For stomach problems specifically, you doctor may request a barium meal test.
The stool may contain substances that can verify the presence of certain stomach disorders. Considering that the stomach contents have a long way to pass through the gut before it becomes part of the stool, it may not always be helpful for diagnosing every type of stomach problem. One of the common stool tests that are performed is the fecal occult blood test. It is able to detect even small amounts of blood in the stool. This may indicate bleeding from the stomach. But there are many causes of blood in the stool and there is no way of knowing the exact site of the bleeding through this type of stool test.
Another type of stool test that is done to identify problems in the stomach is the stool antigen test to check for H.pylori infection. Helicobacter pylori (H.pylori) is a type of bacteria that is one of the causes gastritis or even peptic ulcer disease (PUD). The stool antigen test checks for the presence of substances from the bacteria that is passed out in the stool. It is these substances (antigens) that trigger the immune system to fight the bacteria. A positive test confirms the diagnosis of H.pylori infection but other tests should be used to confirm the exact stomach problem. It is also helpful to confirm the effectiveness of H.pylori eradication treatment.
There are a number of different blood tests that may be used for different stomach problems. Some can measure the body’s response to certain microbes infecting the stomach while others assess the levels of different hormones that influence stomach activity. One of the more common blood tests for stomach problems is the H.pylori blood antibody test. It measures the immune system’s activity against the H.pylori bacteria that can infect the stomach. A positive test means that you currently have the infection or had it previously.
A serum pepsinogen test measures the amount of the inactive form of the digestive enzyme known as pepsin which is secreted by the stomach lining. A very small amount of these pro-enzymes leak into the bloodstream and can be detected with a blood test. Serum pepsinogen is helpful in estimating the gastric pH and has been proposed as a stomach cancer screening test. The gastrin test measures the amount of the hormone gastrin in the bloodstream. This hormone stimulates the production of gastric acid. Another related investigation is the gastrin stimulation test which may be used to investigate a possible gastrinoma (gastrin-producing tumor).
A breath test, as the name suggests, assesses the air that you breathe out to identify possible stomach problems. There are a number of different breath tests that can be conducted for gastrointestinal conditions. The more common of these for the stomach is the urea breath test. It is used to confirm the presence of H.pylori bacteria in the stomach. In order to conduct this test, you will have to swallow a small amount of urea with a carbon isotope.
If the H.pylori bacteria are present then it will split the urea and carbon isotope will be released with the breath. H.pylori are able to do this because these bacteria have the enzyme urease to split urea. Recently another type of breath test has been unveiled which may help with the diagnosis of stomach cancer. It is still in the early stages and therefore not widely available. If thorough clinical studies can confirm its effectiveness in identifying stomach cancer, it will greatly contribute to quicker screening for this type of malignancy.
CT, PET and MRI
These scans use different techniques to visualize the stomach without having to enter the stomach like with an upper GI endoscopy. Although it is less invasive, it can still be very effective in identifying certain types of stomach problems. Your doctor will decide which of these types of scans are necessary for your case. It is usually done to map the entire area around the stomach and not just the stomach alone.
- Computerized tomography (CT) scan is a type of X-ray where a series of images are taken from different angles. The computer then uses these X-rays to form cross-sectional images of your stomach and other organs.
- Positron emission tomography (PET) scan uses radioactive material to visualize the stomach. It allows for the functioning of the stomach to be assessed and diseased tissue to be identified.
- Magnetic resonance imaging (MRI) uses a combination of magnetic and radio waves to create highly detailed 3D images of the stomach. It does not require the use of radioactive materials.
An abdominal ultrasound is another type of imaging techniques. Sound waves that bounce off the abdominal organs are analyzed by a computer to create images.
The stomach produces acid as well as enzymes to aid with chemical digestion of food. Sometimes the volume and pH of this acid may be abnormal in certain diseases. Therefore it is helpful to assess the stomach acid as part of diagnosing certain diseases. The more widely known esophageal 24 hour pH test is done to measure esophageal conditions like gastroesophageal reflux disease (GERD) and not stomach problems. The stomach acid test, also known as the HCl test, is done for the stomach specifically.
In the stomach acid test, a small sample of the stomach contents is collected through a nasogastric tube. It should only be done after fasting for 4 to 6 hours. Sometimes the hormone gastrin is injected into the bloodstream to increase stomach acid production. It will help with assessing whether the stomach is producing too much or too little acid. A litmus test can be done to measure the pH of the sample or a pH electrode can be used to measure the pH of the stomach acid at the time of an upper endoscopy.