no symptoms for many weeks, months, or even years before another episode or flare occurs.
Because these flares often subside on their own, patients will sometimes not go to the doctor for investigation or treatment, until an episode is more severe, lasts longer than usual, or is more concerning in some way.
Diagnostic Methods
If you suspect you or a family member is experiencing any symptoms of inflammatory bowel disease, be sure to see your doctor as soon as possible. A medical history of symptoms and a physical examination are usually adequate for strongly suspecting a diagnosis of Crohn’s disease or ulcerative colitis, but further diagnostic testing is important in confirming the suspected diagnosis, determining the extent and severity of the disease, and screening for possible complications of the disease. These procedures include standard blood and stool tests, various imaging studies, endoscopies, and biopsy.
Not all tests or investigations are required in all patients. The tests chosen will depend on your specific symptoms, as well as the availability, potential risk, and discomfort of the specific investigation.
Diagnostic Tests for IBD
•Blood tests
•Stool tests
•Imaging studies
-X-ray
-Ultrasound
-CT scan
-MRI
•Endoscopy
-Gastroscopy
-Colonoscopy
-Wireless capsule endoscopy
-Enteroscopy
•Biopsies
Blood Tests
White blood cell or platelet count can increase in infections and inflammatory conditions and can be elevated in active IBD. Certain antibodies are found more frequently in the blood of patients with IBD. Antibodies are proteins produced by the immune system to defend against certain types of infection by binding to specific molecules found on the surface of viruses and bacteria. Some proteins, most commonly C-reactive protein, are found in higher levels in the blood of people with inflammatory conditions.
Screening
Although blood tests cannot replace more definitive diagnostic tests, such as imaging studies, endoscopy, or biopsy, and although they cannot yet be used to confirm a diagnosis, they may be helpful in screening out patients with possible IBD before proceeding to more definitive and often invasive diagnostic testing.
Antibody Patterns
The pattern of antibodies may help differentiate between ulcerative colitis and Crohn’s disease. The antibodies found in the blood in IBD include anti-ompC, anti-CBir1, and anti-fla-X, among others. These are antibodies that target certain proteins found on bacteria. They have been combined in a commercially available blood test panel with some other proteins and genetic markers found in blood; together, these markers provide a probability of a given individual having IBD. One of these antibodies, called perinuclear antineutrophil cytoplasmic antibody (pANCA), occurs more commonly in ulcerative colitis, whereas another antibody, anti-Saccharomyces cerevisiae antibody (ASCA), is fairly specific for Crohn’s disease.
There are several other antibody tests that are commercially available along with pANCA and ASCA. Although this panel of antibody tests cannot replace more definitive diagnostic tests, such as imaging studies, endoscopy, or biopsy, and although they cannot yet be used to confirm a diagnosis of IBD, they may be helpful in screening out patients with possible IBD before proceeding to more definitive and often invasive diagnostic testing. This may be particularly helpful in children, where invasive diagnostic testing is more difficult to justify and carry out, particularly when the suspicion of actually finding disease is relatively low. These antibody tests can be used to help determine who should undergo further testing, since it is very unlikely that a child with a negative pANCA and ASCA test will turn out to have IBD. It also appears that, in a patient with known Crohn’s disease or ulcerative colitis, certain patterns of the different antibodies, and the levels of antibodies present in the blood, may be associated with certain disease locations and with higher risk of developing certain complications of disease.
Other blood tests indicate evidence of possible complications or nutritional deficiencies that may have occurred as a result of IBD. These include blood tests for anemia, liver disease, iron deficiency, vitamin B12 deficiency, and calcium deficiency.
| What tests will my doctor recommend? | |
| When recommending a specific test or series of tests, your doctor will take into account several factors. First, the choice of test is determined by your symptoms and what your doctor considers to be the likely diagnosis or possible site of disease. Second, the need to search for possible complications of IBD is considered when ordering tests. After taking these two factors into consideration, your doctor will then consider the accuracy of the diagnostic test, particularly if there are two or more possible tests that could provide similar information. In addition, some tests may have degrees of risk of complication or discomfort. The availability of the tests needs be taken into consideration since not all tests will be available in all communities or geographic areas. Third, the doctor will consider your special needs. Tests that would be ordered readily on adults might not be so appealing in children. Some patients may have had very bad experiences with certain tests or may be very afraid of other types of tests. |
Stool Tests
Stool samples may be sent for culture to rule out a bacterial infection as the cause for a patient’s symptoms. While the yield from this is quite low, particularly when symptoms have been going on for many weeks or even months, it is important to rule out infections before embarking on many types of therapy for Crohn’s disease and ulcerative colitis.
Stool may also be examined for parasites or the eggs of parasites. Occasionally, the laboratory will report that no parasites were seen, but that many white blood cells are present in the stool. The presence of white blood cells almost always indicates some type of inflammatory condition in the intestine. Stool can also be tested for certain proteins — calprotectin and lactoferrin — that are present in white blood cells that indicate the presence of active intestinal inflammation. The calprotectin level in stool has proven to be quite useful in people who present with symptoms that are not clearly or highly likely to be due to IBD. In that situation, an elevated calprotectin level is very suggestive of an underlying inflammatory condition such as IBD, and would support going ahead with other testing, such as endoscopy and biopsy, that can confirm the diagnosis.
Disease Activity
Stool tests can be used to monitor disease activity and response to treatment. These tests, when combined with blood tests, help make decisions regarding changes in treatment strategies.
X-Rays
Since the intestine does not appear in sufficient detail on plain X-rays, a contrast agent, usually barium, is used to fill the intestine so that the intestinal lining and wall can be seen in contrast to the barium. The barium is administered in several ways, depending on the area of bowel under examination. Because of the two-dimensional limitation of these techniques, they have been largely replaced by cross-sectional imaging studies, such as ultrasound, CT scan, and MRI.
Upper GI Series and Small Bowel Follow-Through
When examining the small intestine, the barium can be given by having the person drink it. X-rays are taken every few minutes as the barium passes out of the stomach and through the small intestine. This type of X-ray can also detect problems in the esophagus, stomach, and duodenum. It requires no preparation on the