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.
If your doctor has asked you to do a calprotectin stool test, you may be wondering how to provide a sample — and what it will show.
Fecal matter, also known as stool or poop, can provide information about conditions that affect your gastrointestinal tract. These include:
- inflammatory bowel disease (IBD), which includes ulcerative colitis (UC) and Crohn’s disease
- irritable bowel syndrome (IBS)
- bacterial or viral infections
Read on to learn all about the calprotectin stool test, including how it’s done and what it can (and can’t) tell you about your intestinal tract.
The calprotectin stool test is noninvasive.
This test is helpful for detecting and measuring inflammation levels in the intestines. The information it provides may eliminate the need for more invasive tests, like a colonoscopy or sigmoidoscopy.
The calprotectin stool test isn’t used to make a definitive diagnosis of any condition. It’s beneficial for determining whether additional diagnostic steps are needed.
What is calprotectin?
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 that area of the body and release calprotectin in an effort to fight off disease or infection.
Inflammation in the gastrointestinal tract can be an indication of IBD. IBD is an umbrella term for chronic conditions that cause prolonged inflammation in the digestive tract. Examples of IBD include:
The calprotectin stool test can help your doctor diagnose IBD. It can also be used to monitor the severity of IBD flare-ups after diagnosis.
This test helps distinguish between IBD and IBS. IBS is a noninflammatory bowel condition often with similar symptoms.
High levels of calprotectin in stool may also indicate other conditions like:
- bacterial infection
- parasitic infection
- colorectal cancer
IBD symptoms vary based on the location and severity of inflammation in the GI tract. Since ulcerative colitis and Crohn’s disease can flare up and recede over time, your symptoms may be chronic (long lasting) or acute (short term).
Many symptoms of IBD, including those of ulcerative colitis and Crohn’s disease, can also be caused by IBS, certain cancers, or infections.
Some or all of these symptoms may signal the need for a calprotectin stool test:
- watery diarrhea
- bloody diarrhea
- cramping
- stomach pain
- unexplained weight loss
- rectal bleeding
- bloating
To take this test, you’ll need to provide a stool sample. The consistency of stool won’t affect the diagnostic ability of the test.
Your doctor may instruct you to eliminate certain substances for days or weeks before the test. These include:
- nicotine products
- alcoholic beverages
- pain medications like nonsteroidal anti-inflammatory drugs (NSAIDs)
Your doctor will give you a sterile container to collect your sample. It’s very important that the sample you provide not touch any surface other than the container. It’s also important that water and urine aren’t included in your sample. These substances can skew your test results.
Stool collection instructions
- Before you collect your sample, fill in the label on the container with your name and any other additional information that’s required.
- Wear disposable plastic gloves to avoid soiling your hands or transferring fecal matter to other areas of your 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.
How long will it take to receive results?
The amount of calprotectin in your stool will be measured in a laboratory. Based on the laboratory used, your results may take several days to 1 week.
High levels of calprotectin in stool may signal ulcerative colitis, Crohn’s disease, colorectal cancer, or infection.
Moderate or low levels mean there’s little to no inflammation present in the intestines. This may indicate that your symptoms are caused by a viral infection or IBS.
Calprotectin levels are measured within a reference range of numerical values indicated as μg/g (micrograms per gram). According to the University of Iowa Dept. of Pathology Laboratory Services Handbook, the reference range for the calprotectin stool test is:
| Normal (low, no inflammation) | Moderate (borderline elevated) | High |
| 49 μg/g or less | 50–120 μg/g | 121 μg/g or greater |
Next steps
- Normal (low, no inflammation) results: If your levels are low, your doctor may recommend self-care measures, like dietary changes, relaxation, and exercise for symptom relief. Antidiarrheal and antispasmodic medications may also be given.
- Moderate (borderline elevated) results: If your levels are borderline elevated, your doctor may recommend retesting in several weeks, along with medication to alleviate symptoms. If bacterial infection is suspected, antibiotics may be given.
- High results: If your levels are high, additional diagnostic tests, like a colonoscopy, will be done. This will help provide diagnostic information and determine the next steps for your care.
The calprotectin stool test is a noninvasive test that helps distinguish between IBD, including ulcerative colitis and Crohn’s disease, and IBS. It may also signal the presence or absence of an infection or colorectal cancer.
The test involves providing a fecal (stool) sample to a laboratory. The laboratory analyzes the stool sample and sends the results to your doctor. Your doctor uses these results to determine whether additional testing is needed.