IBS Tests and Exams
The cause(s) of IBS is not known. Some experts believe it may come from certain foods or food allergies. Some others postulate that the origin may be genetic and still others suspect it is stress-related. The signs and symptoms have been categorized to differentiate IBS from more serious organic bowel disease.
IBS is a diagnosis of exclusion. All other possible conditions must be excluded before someone is diagnosed with the disorder. A thorough history and physical exam will help tremendously in narrowing the possible causes. Suspicions can be confirmed or ruled out with lab studies, imaging studies, and medical procedures.
Lab Studies:
CBC (complete blood count): will help to rule out infection, blood loss, inflammation
Electrolytes: checks for dehydration, diarrhea, loss of electrolytes and acid-base disturbances
Heme-Occult Test: checks for chronic loss of blood as can occur with a slow GI bleed
Stool: can be examined for infectious agents by checking for
1) ova and parasites
2) toxins (C. difficle toxin)
3) high counts of leukocytes
Breath Test: tests for intolerance of sugars (lactose and fructose)
Thyroid Function Tests (TFTs): is to rule out hyperthyroidism or hypothyroidism. Symptoms of both can mimic IBS.
Serum Calcium: is important in checking for hyperparathyroidisam. High serum calcium may cause abdominal symptoms similar to IBS.
Erythrocyte Sedimentation Rate (ESR) or C-Reactive Protein (CRP): are tests used to detect inflammatory conditions. The ESR increases with inflammatory conditions and C-reactive Protein is a glycoprotein produced acutely with inflammation or tissue injury.
Serologies/Bowel biopsy: are for suspected ulcers or inflammatory bowel diseases (e.g., Crohn’s, ulcerative colitis). Mucosal tissue may have to be biopsied and tested for confirmation of diagnosis.
Hydrogen Breath Test, D-xylose Test, and Fecal Fat Test: are all used to test for malabsorption
Imaging Studies:
Upper GI Barium Study: an x-ray is used to check for structural abnormalities and inflammation from the esophagus to the small intestines after barium is swallowed.
Double Contrast Barium: is also used to examine mucosal surfaces of the GI tract for abnromalities.
Ultrasound: is great for evaluating many structures in the GI system (liver, gallbladder, stomach, etc.) to visualize abnormalities such as a mass or a presence of fluids.
CT scan: provides very good information about possible structural abnormalities and inflammatory conditions.
GI procedures
Endoscopy: A scope is introduced orally or nasally to check for problems in the upper GI tract. If necessary, a biopsy can be taken.
Colonoscopy: A scope is introduced through the anal canal and rectum to examine the mucosal surface of the colon for any abnormalities. If there are questionable structures, a sample can be biopsied.