A calprotectin stool test may help determine whether you have an inflammatory or noninflammatory bowel condition. The information it provides may also eliminate the need for more invasive tests.
A calprotectin stool test is a noninvasive test that may help detect and measure inflammation levels in your intestine.
Calprotectin is a protein manufactured by white blood cells in response to inflammation. When there’s inflammation in the intestines, white blood cells called neutrophils travel to the inflamed area and release calprotectin to fight off disease or infection.
High levels of calprotectin in your stool may be an indication of a health condition affecting your gastrointestinal tract, such as:
- inflammatory bowel disease (IBD), including ulcerative colitis and Crohn’s disease
- bacterial, viral, or parasitic infections
- colorectal or intestinal cancer
Keep reading to learn more about how a calprotectin stool test is done and what it can tell you about your intestinal tract.
A healthcare professional may recommend a calprotectin stool test if you’re experiencing gastrointestinal symptoms, such as:
- watery or persistent diarrhea
- abdominal cramping
- blood or mucus in your stool
- black, tarry stools
- stomach pain
- frequent, urgent need to have a bowel movement
- unexplained weight loss
- rectal bleeding
- bloating
Many of these symptoms may be caused by IBD, such as ulcerative colitis and Crohn’s disease. However, they can also be caused by irritable bowel syndrome (IBS), certain cancers, or infections.
A calprotectin test could help a doctor check for intestinal inflammation, which can help them determine whether you need further testing for the underlying cause.
If you’re experiencing non-alarm symptoms like diarrhea, bloating, and mucus in your stool, a doctor may recommend a calprotectin test.
According to the United Kingdom’s National Health Service, the test has a 90% specificity and sensitivity rate to differentiate between IBS and IBD.
However, if you’re experiencing alarm symptoms like blood in your stool or unexplained weight loss, you will need a calprotectin test and a colonoscopy.
A doctor may also recommend regular calprotectin tests to help monitor your response to treatment if you have IBD.
Calprotectin levels could also help predict IBD flare-ups in people with IBD. People who have no symptoms but have high calprotectin levels have an
To take this test, you’ll need to provide a stool sample. The consistency of the stool will not affect its diagnostic ability.
A doctor will give you a sterile container to collect your sample.
It’s important that the sample you provide does not touch any surface other than the container and that water and urine aren’t included in it. These substances can skew test results.
Stool collection instructions
- Before you collect your sample, fill in the label on the container with your name and any other required information.
- Wear disposable plastic gloves to avoid soiling your hands or transferring fecal matter to other areas of the bathroom.
- Sit on the toilet bowl normally. Hold the container to your anus while providing a sample. Hard stool should be at least 1 inch long in diameter. Try to include at least that much fecal matter.
- Alternatively, you can cover the inside of the toilet bowl with plastic wrap or place a large, clean container in the toilet bowl to collect your sample. The sample can then be transferred to the container your doctor provided.
- Dispose of the gloves and other materials used for sample collection.
- Wash your hands.
- Your stool sample should be returned to your doctor or directly to the laboratory as soon as possible. It will become untestable after 3 days.
Medical perspective“It’s important not to drink alcohol or smoke within at least 24 hours before your calprotectin test, as these may skew your test results. Some medications, such as nonsteroidal anti-inflammatory drugs (NSAIDs), may also affect your test results.
Consider speaking with your doctor about anything you should avoid before your test.”
— Qin Rao, MD
Quotes represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.
How long will it take to receive results?
The amount of calprotectin in your stool will be measured in a laboratory. Your results will usually be available within 5 days. However, times may vary depending on the laboratory.
High calprotectin levels in your stool indicate intestinal inflammation, which may be a sign of ulcerative colitis, Crohn’s disease, colorectal cancer, or infection.
Moderate or low levels mean there’s little to no inflammation in the intestines, so your symptoms are likely caused by a noninflammatory bowel condition.
The following table presents normal, moderate, and high calprotectin levels, which are measured in micrograms per gram (μg/g) and presented within a reference range of numerical values:
| Normal (low, no inflammation) | Moderate (borderline elevated) | High |
| 49 μg/g or less | 50 to 120 μg/g | 121 μg/g or greater |
Next steps
- Normal (low, no inflammation) results: If you’re not experiencing alarm symptoms, a doctor may diagnose IBS and recommend self-care measures and antidiarrheal or antispasmodic medications to relieve symptoms.
- Moderate (borderline elevated) results: A doctor may recommend retesting in several weeks, along with medication to alleviate symptoms.
- High results: Additional diagnostic tests will be done, such as a colonoscopy or sigmoidoscopy. This will help provide diagnostic information and determine the next steps for your care.
What does high calprotectin in stool mean?
High calprotectin in your stool may indicate an underlying health condition, such as ulcerative colitis, Crohn’s disease, bacterial infection, or some types of cancer.
What level of calprotectin indicates Crohn’s disease?
Calprotectin results above 121 μg/g are a marker of intestinal inflammation, which may indicate an underlying condition like Crohn’s disease. The United Kingdom’s North Bristol NHS Trust notes that people with levels above 250 μg/g have a 46% chance of having IBD.
What does a fecal calprotectin test for?
A fecal calprotectin tests for inflammation in the intestine.
What cancers cause high calprotectin?
Some cancers that may cause high calprotectin include colorectal and intestinal cancers.
The calprotectin stool test is a noninvasive test that helps distinguish between IBD and IBS. It may also signal the presence or absence of an infection or colorectal cancer.
The test involves providing a stool sample to a laboratory. The laboratory analyzes the stool sample and sends the results to your doctor, who uses them to determine whether additional testing is needed.