Calprotectin Stool Test
A calprotectin stool test measures levels of a specific protein in your stool to detect inflammation in the intestines, helping providers distinguish between different digestive conditions.
What is a calprotectin stool test?
A calprotectin stool test, also called a fecal calprotectin test, measures a protein called calprotectin in a sample of your stool. It is used to check for inflammation (swelling and irritation) in your intestines.
While it is normal to have a small amount of calprotectin in your stool, high levels indicate intestinal inflammation. When inflammation occurs, your immune system sends white blood cells called neutrophils to the area, which release calprotectin into the intestines where it mixes with your stool.
Intestinal inflammation can cause severe watery or bloody diarrhea, abdominal pain, and cramping. Because this inflammation can damage the lining of your intestines over time, this test helps providers determine if your symptoms are related to inflammation, though it cannot diagnose a specific cause.
What is it used for?
Providers primarily use this test to help distinguish between inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS), as both conditions share similar symptoms like diarrhea, belly pain, and cramps.
- IBD: A group of digestive diseases, including Crohn's disease and ulcerative colitis, that involve inflammation and can damage the lining of the intestines.
- IBS: A group of symptoms—such as bloating, pain, and changes in bowel habits—caused by issues with how the brain and gut work together. IBS does not involve inflammation or damage to the intestines.
For patients already diagnosed with IBD, the test is used to assess the severity of inflammation, guide treatment choices, monitor if the condition is improving or worsening, and predict the return of symptoms.
Why do I need a calprotectin stool test?
If you experience persistent diarrhea, belly pain, or cramping that does not improve after a few days, your provider may order this test. Other symptoms of intestinal inflammation include:
- Blood, mucus, or pus in your stool (seek immediate care if stool is black and tarry).
- A constant, painful feeling of needing to move your bowels.
- An urgent need to move your bowels.
- Unexplained weight loss.
What happens during a calprotectin stool test?
You will need to provide a stool sample using a container or kit provided by your health care provider. General instructions include:
- Labeling the container with your name, date, and time of collection.
- Collecting the sample using a clean, dry container or special paper/plastic wrap to catch the stool.
- Ensuring the stool does not mix with urine, toilet paper, or toilet water.
- Closing the container tightly and washing your hands thoroughly.
Preparation and Risks
Ask your provider if you need to stop taking any medications, such as nonsteroidal anti-inflammatory drugs (NSAIDs) like aspirin or ibuprofen, or proton pump inhibitors (PPIs) like omeprazole, as these may affect results. Never stop taking medication without consulting your provider first. There are no known risks to this test.
What do the results mean?
- Normal or low levels: Usually indicate no intestinal inflammation and suggest you do not have IBD. However, "false negatives" can occur, particularly in children.
- High levels: Indicate intestinal inflammation. The higher the level, the more inflammation is present.
Very high levels are often linked to IBD or bacterial food poisoning. Somewhat high levels may be linked to colorectal cancer, celiac disease, Clostridium difficile (C. diff), NSAID use, or treated IBD. If results indicate inflammation, your provider may order a colonoscopy to determine the specific cause.