The calprotectin stool test is a simple, non-invasive lab test that measures calprotectin in a stool sample to detect intestinal inflammation. It is commonly used to help distinguish inflammatory bowel disease (IBD) from functional conditions like irritable bowel syndrome (IBS), and to monitor disease activity over time. This guide explains what calprotectin is, how the test works, how to prepare, what your results mean, and how it fits with gut microbiome insights.

What is a calprotectin stool test?

Calprotectin is a protein released by neutrophils, a type of immune cell, when there is inflammation in the intestinal lining. The calprotectin stool test measures the level of this protein in a stool sample. It is a non-invasive biomarker that helps clinicians assess whether inflammation is present in the gut, which can aid in diagnosing and monitoring conditions like Crohn's disease and ulcerative colitis.

What does a calprotectin stool test measure?

The test quantifies the concentration of calprotectin in stool, usually reported in micrograms per gram (µg/g). It reflects neutrophil activity in the gut lumen, which increases when the intestinal mucosa is inflamed. It does not identify the cause of inflammation, such as infection, IBD, or other conditions, but it provides objective evidence that inflammation is present.

Why is it used?

Clinicians use the calprotectin stool test to help differentiate inflammatory conditions (like IBD) from non-inflammatory ones (like IBS). It is also used to monitor disease activity in people already diagnosed with IBD, and to help decide whether further invasive testing, such as colonoscopy, is needed.

How to prepare for a calprotectin stool test

Preparation is straightforward, but there are a few important steps to ensure accurate results.

1. Collect a small stool sample using the provided collection kit. Follow the instructions carefully to avoid contamination.
2. Avoid taking non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen for a few days before the test, if possible, as they can raise calprotectin levels.
3. Inform your clinician about any medications you are taking, including proton pump inhibitors, and any recent infections or procedures.
4. Store and transport the sample as directed, usually in a refrigerator or with a cold pack, to maintain stability.

What not to do before a calprotectin test?

Avoid taking NSAIDs and proton pump inhibitors if possible, as they can falsely elevate calprotectin. Also, avoid heavy exercise and alcohol for a day or two before the test, as these can also affect levels. Always consult your clinician before stopping any prescribed medication.

Calprotectin normal vs. high levels: what do they mean?

Calprotectin levels are typically interpreted using the following ranges, though exact cutoffs may vary by laboratory:

• Normal: often below 50 µg/g — low likelihood of significant intestinal inflammation.
• Borderline: roughly 50–150 µg/g — may require repeat testing or correlation with symptoms and other tests.
• Elevated: often above 150 µg/g — suggests active intestinal inflammation and warrants further evaluation.

What level of calprotectin is concerning?

Levels above 150 µg/g are generally considered concerning and indicate significant intestinal inflammation. However, the degree of elevation does not always correlate with disease severity, and some people with active IBD may have lower levels. Your clinician will interpret the result in the context of your symptoms and other tests.

What does a high calprotectin level mean?

A high calprotectin level indicates that there is inflammation in your intestines. This could be due to inflammatory bowel disease (IBD), an infection, or other causes. It does not diagnose a specific condition, but it is a strong signal that further investigation is needed to find the underlying cause.

What level of calprotectin indicates Crohn's disease?

There is no specific calprotectin level that definitively indicates Crohn's disease. Elevated levels (typically above 150 µg/g) increase the likelihood of IBD, but a diagnosis requires endoscopic and histologic confirmation. Levels above 250 µg/g are often used in clinical practice to identify patients who are likely to have IBD and may benefit from colonoscopy.

What level of fecal calprotectin indicates IBD?

Fecal calprotectin levels above 150 µg/g are commonly used as a threshold to suggest IBD, but levels can vary. Some studies use 200 µg/g or higher to increase specificity. Your clinician will use the result along with symptoms, blood tests, and imaging to determine if IBD is likely.

What can falsely elevate calprotectin?

Several factors can cause calprotectin levels to be higher than they would be otherwise, leading to false positives. These include:

• Use of NSAIDs (e.g., ibuprofen, naproxen)
• Proton pump inhibitors (PPIs) for acid reflux
• Recent gastrointestinal infections (bacterial, viral, or parasitic)
• Recent colonoscopy or bowel surgery
• Heavy exercise or intense physical activity

If you have any of these factors, your clinician may recommend repeating the test after avoiding them for a period of time.

What can a calprotectin test detect?

A calprotectin test detects the presence of intestinal inflammation. It is not a specific test for any single disease, but it can help identify conditions that cause inflammation, such as:

• Inflammatory bowel disease (Crohn's disease, ulcerative colitis)
• Infectious colitis (bacterial, viral, or parasitic)
• Ischemic colitis (reduced blood flow to the colon)
• Microscopic colitis

It is not a tumor marker, but high levels can sometimes be seen in colorectal cancer due to inflammation. However, calprotectin is not used to screen for cancer.

Is calprotectin a tumor marker?

No, calprotectin is not a tumor marker. It is a marker of inflammation. While some cancers can cause inflammation and elevated calprotectin, the test is not used to diagnose or screen for cancer. If cancer is suspected, other tests such as colonoscopy and imaging are needed.

What cancers cause high calprotectin?

High calprotectin is not specific to cancer, but colorectal cancer can cause elevated levels due to the inflammatory response around the tumor. Other gastrointestinal cancers may also increase calprotectin, but this is not a reliable screening method. If you have elevated calprotectin and concerning symptoms, your clinician will recommend appropriate investigations, including colonoscopy, to rule out malignancy.

Does a high level of calprotectin need a colonoscopy?

A high calprotectin level often prompts a colonoscopy, especially if you have symptoms like diarrhea, abdominal pain, or weight loss. The test helps identify who is likely to have inflammation and would benefit from direct visualization of the colon. However, not everyone with elevated calprotectin needs a colonoscopy; your clinician will consider your overall clinical picture.

What level of calprotectin warrants a colonoscopy?

There is no absolute cutoff, but levels above 150 µg/g are often used as a threshold to consider colonoscopy, especially if symptoms are present. Some guidelines suggest 250 µg/g or higher to increase the likelihood of finding IBD. Your clinician will use the result along with other factors to decide if a colonoscopy is necessary.

How is calprotectin measured?

Calprotectin is measured using laboratory techniques such as enzyme-linked immunosorbent assay (ELISA) or immunoassay. These methods use antibodies to detect and quantify the calprotectin protein in a stool sample. Results are reported in µg/g. Point-of-care tests are also available, but they may have different accuracy and cutoffs compared to lab-based tests.

How to read calprotectin results

Your calprotectin result will be a number in µg/g. Compare it to the reference range provided by the lab. A result below 50 µg/g is usually considered normal. Between 50 and 150 µg/g is borderline, and above 150 µg/g is elevated. However, these ranges can vary, so always discuss your result with your clinician, who will interpret it in the context of your symptoms and medical history.

What autoimmune disease causes high calprotectin?

Inflammatory bowel disease, which includes Crohn's disease and ulcerative colitis, is an autoimmune-related condition that causes high calprotectin. Other autoimmune diseases that affect the gut, such as microscopic colitis, can also elevate calprotectin. However, calprotectin is not specific to autoimmune diseases; infections and other inflammatory conditions can also raise levels.

Can food cause high calprotectin?

Food itself does not directly cause high calprotectin, but certain dietary patterns may influence gut inflammation. For example, a diet high in processed foods and low in fiber may promote dysbiosis and inflammation, which could contribute to elevated calprotectin in some people. However, food is not the primary cause of high calprotectin; underlying medical conditions are. If you have elevated calprotectin, it is important to seek medical evaluation rather than trying to manage it with diet alone.

What does high protein in the stool mean?

High protein in the stool, specifically calprotectin, indicates intestinal inflammation. Other proteins, such as albumin, can also appear in stool due to conditions like protein-losing enteropathy. Calprotectin is the most commonly measured protein for gut inflammation. If you have high protein in your stool, your clinician will determine the cause based on the specific protein and your symptoms.

What if calprotectin is positive?

If your calprotectin test is positive (elevated), it means there is inflammation in your intestines. This is not a diagnosis, but it indicates that further evaluation is needed. Your clinician may recommend blood tests, stool tests for infection, imaging, or a colonoscopy to determine the cause of the inflammation.

The role of the gut microbiome in inflammation

The gut microbiome plays a significant role in regulating inflammation. Dysbiosis, or an imbalance in gut bacteria, can contribute to increased intestinal permeability and immune activation, which may lead to higher calprotectin levels. Microbiome testing can provide insights into your microbial composition and diversity, helping you understand potential contributing factors to inflammation.

How microbiome testing complements calprotectin

While calprotectin measures inflammation, microbiome testing looks at the community of microbes in your gut. Combining both can give a more complete picture of your gut health. For example, if you have elevated calprotectin and low microbial diversity, it may suggest that dysbiosis is contributing to inflammation. Microbiome testing can guide dietary and lifestyle strategies to support a healthier microbiome, but it does not replace medical diagnosis.

When to see a clinician

You should discuss calprotectin testing with a clinician if you have persistent or unexplained gastrointestinal symptoms such as chronic diarrhea, abdominal pain, bloating, unintentional weight loss, or blood in the stool. If you have red flags like severe pain, high fever, or dehydration, seek urgent medical care. A clinician can help you decide if a calprotectin test is appropriate and interpret the results in the context of your overall health.

Key takeaways

• The calprotectin stool test is a non-invasive marker of intestinal inflammation.
• Normal levels are typically below 50 µg/g; elevated levels are above 150 µg/g.
• High calprotectin indicates inflammation but does not diagnose a specific condition.
• Avoid NSAIDs and PPIs before testing to prevent false elevations.
• Elevated calprotectin often leads to further evaluation, such as colonoscopy.
• Microbiome testing can provide context but does not replace clinical diagnosis.

Frequently asked questions

What does it mean if my calprotectin is high?

A high calprotectin level means there is inflammation in your intestines. It is a signal that further investigation is needed to find the cause, which could be IBD, infection, or other conditions. Your clinician will guide you on next steps.

What is the main cause of high calprotectin?

The most common cause of high calprotectin is inflammatory bowel disease, including Crohn's disease and ulcerative colitis. However, infections, NSAID use, and other inflammatory conditions can also cause elevated levels.

Can food cause high calprotectin?

Food does not directly cause high calprotectin, but a diet that promotes gut inflammation may contribute. If you have elevated calprotectin, it is important to seek medical evaluation rather than relying on dietary changes alone.

What level of calprotectin is concerning?

Levels above 150 µg/g are generally considered concerning and warrant further evaluation. However, the exact threshold may vary by lab, and your clinician will interpret the result in context.

What not to do before a calprotectin test?

Avoid NSAIDs, proton pump inhibitors, and heavy exercise before the test, as they can falsely elevate calprotectin. Also, inform your clinician about any recent infections or procedures.

Does a high level of calprotectin need a colonoscopy?

A high calprotectin level often leads to a colonoscopy, especially if you have symptoms. It helps identify inflammation and allows for biopsy to confirm a diagnosis. Your clinician will decide if it is necessary based on your overall picture.

What level of calprotectin indicates Crohn's disease?

There is no specific level that indicates Crohn's disease, but levels above 150 µg/g increase the likelihood. A diagnosis requires endoscopic and histologic confirmation.

What cancers cause high calprotectin?

Colorectal cancer can cause high calprotectin due to inflammation, but calprotectin is not a cancer screening test. Other cancers are less commonly associated with elevated calprotectin.

What autoimmune disease causes high calprotectin?

Inflammatory bowel disease is the main autoimmune-related condition that causes high calprotectin. Other autoimmune conditions affecting the gut, like microscopic colitis, can also elevate levels.

What does high protein in the stool mean?

High protein in the stool, particularly calprotectin, indicates intestinal inflammation. Other proteins may appear due to different conditions, so your clinician will interpret the specific findings.

What if calprotectin is positive?

A positive calprotectin test means inflammation is present. It is not a diagnosis, but it indicates that further evaluation, such as colonoscopy or additional tests, is needed to determine the cause.

How to read calprotectin results?

Compare your result to the lab's reference range. Below 50 µg/g is normal, 50–150 µg/g is borderline, and above 150 µg/g is elevated. Always discuss with your clinician for proper interpretation.

What can a calprotectin test detect?

It detects intestinal inflammation, which can be caused by IBD, infections, or other conditions. It does not identify the specific cause.

What level of fecal calprotectin indicates IBD?

Levels above 150 µg/g are commonly used to suggest IBD, but higher thresholds like 200–250 µg/g may be used for greater specificity. Your clinician will interpret the result.

What does calprotectin in stool tell you?

It tells you whether there is inflammation in your intestines. This helps guide further diagnostic steps and monitoring of inflammatory conditions.

What to avoid before a calprotectin test?

Avoid NSAIDs, PPIs, and heavy exercise. Also, avoid taking stool softeners or laxatives that could dilute the sample. Follow your clinician's instructions.

What level of calprotectin warrants a colonoscopy?

Levels above 150 µg/g often warrant a colonoscopy, especially with symptoms. Some guidelines use 250 µg/g as a threshold. Your clinician will decide based on your individual situation.

Is calprotectin a tumor marker?

No, calprotectin is not a tumor marker. It is a marker of inflammation and is not used to screen for cancer.

Next steps for your gut health

If you are considering a calprotectin stool test, talk to your clinician about whether it is appropriate for your symptoms. If you have already received results, discuss them with your clinician to understand what they mean for your health. For additional insight into your gut microbiome, you may consider a gut microbiome test, which can provide information about microbial diversity and potential imbalances. However, remember that microbiome testing is not a diagnostic tool and should be used alongside clinical evaluation.

For those interested in tracking changes over time, a test subscription and longitudinal testing can help monitor your gut health. Clinicians and organizations can explore our B2B gut microbiome platform for programmatic testing options.

Always work with a healthcare provider to interpret test results and create a personalized plan that is safe and effective for you.