Tests
The diagnosis of an IBD is primarily made with non-laboratory tests, but laboratory testing is an important tool for ruling out other causes of diarrhea, abdominal pain, and colitis. These causes can include viral or bacterial infections, parasites, medications, abdominal or pelvic radiation,
colon cancer, and a variety of other chronic conditions such as
celiac disease and
cystic fibrosis.
Laboratory Tests
Tests that may be ordered to rule out other causes of diarrhea and inflammation include:
Stool culture to look for bacterial infection
O&P (Ova and parasite) to detect parasites
Clostridium difficile to detect toxin created by bacterial infection; may be seen following antibiotic therapy
Fecal occult blood to look for blood in the stool
Stool WBC to detect white blood cells in the stool
Celiac Disease tests
Tests that are not specific for IBD but may be done to detect and evaluate the inflammation and anemia associated with IBD include:
ESR (erythrocyte sedimentation rate) to detect inflammation
CRP (C-reactive protein) to look for inflammation
CBC (complete blood count) to check for anemia
There are several tests that are not widely used clinically but that may sometimes be ordered to help differentiate between UC and CD. These tests are not sensitive or specific enough to diagnose either condition, but they may give the doctor additional information. They include:
pANCA (Perinuclear anti-neutrophil cytoplasmic antibody) is found in 60% to70% of those with UC, but only about 5% to 20% of those with CD.
ASCA (Saccharomyces cerevisiae antibodies), IgG and IgA. ASCA IgG is found in 80% of CD patients and in about 20% of those with UC. ASCA IgA is found in 35% of CD patients but in less than 1% of those with UC.
Non-Laboratory Tests
These tests are used to help diagnose and monitor UC and CD. They can be used to look for characteristic changes in the structure and tissues of the intestinal tract and to detect blockages. Care must be taken during an acute attack or flare-up of an IBD, however, as there is a slight chance of perforating the bowel during testing.
X-ray (abdominal), barium contrast dye allows an evaluation of the intestines
Sigmoidoscopy, a slender tube is used to examine the last 2 feet of the colon
Colonoscopy, a slender tube is used to examine the entire colon; it includes a light and camera and can be used to take biopsies
Biopsy, tissue samples from the colon that are evaluated for inflammation and abnormal changes in cell structures
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