Fecal Calprotectin

Overview

Fecal calprotectin is a protein found in stool that serves as a biomarker for intestinal inflammation. It is particularly useful in diagnosing and monitoring conditions like inflammatory bowel disease (IBD), which includes Crohn"s disease and ulcerative colitis^[1]. Calprotectin is a stable protein that makes up about 60% of the cytoplasmic protein content of neutrophils, which are white blood cells involved in inflammation^[2]. Tracking fecal calprotectin levels helps differentiate between inflammatory and non-inflammatory gastrointestinal disorders, such as irritable bowel syndrome (IBS)^[3].

Scientific Background

Calprotectin is a dimer composed of the proteins S100A8 and S100A9, which have bacteriostatic and fungistatic properties by sequestering essential metals like zinc and manganese^[1]. It is released into the gut lumen during inflammation, making it a reliable indicator of neutrophilic activity in the gastrointestinal tract^[2]. Calprotectin"s stability allows it to be easily measured in feces, providing a non-invasive method for assessing intestinal inflammation^[3]. Its levels correlate well with other markers of inflammation, such as 111-indium labeled granulocytes^[1].

Measurement and Testing

Fecal calprotectin is typically measured using immunochemical techniques like ELISA or immunochromatographic assays^[1]. Testing involves collecting a stool sample in a sterile container, which is then analyzed for calprotectin levels^[5]. Factors affecting results include recent use of nonsteroidal anti-inflammatory drugs (NSAIDs) or other medications that may cause gastrointestinal irritation^[4]. Testing is recommended for patients with symptoms suggestive of IBD or other inflammatory conditions^[5].

Reference Ranges

Reference ranges for fecal calprotectin vary by age: for children aged 2-9 years, the upper limit is 166 μg/g; for adults aged 10-59 years, it is 51 μg/g; and for those aged 60 and older, it is 112 μg/g^[1]. Generally, levels below 50 μg/g are considered normal, while levels above 120 μg/g indicate significant inflammation^[4]. Demographic variations and individual health conditions can influence these ranges^[3].

High Values

Elevated fecal calprotectin levels are associated with conditions like IBD, celiac disease, colorectal cancer, and gastrointestinal infections^[2]. High levels indicate active inflammation in the gastrointestinal tract and may be accompanied by symptoms such as diarrhea, abdominal pain, and weight loss^[5]. These conditions pose significant health risks if left untreated, including complications from chronic inflammation and potential malignancy^[4].

Low Values

Low fecal calprotectin levels typically suggest the absence of significant intestinal inflammation, which is common in conditions like IBS^[3]. However, normal levels do not exclude the possibility of IBD, as some cases may not show elevated calprotectin^[4]. Low levels are generally associated with a lower risk of inflammatory conditions but require clinical correlation for accurate interpretation^[5].

Improving Biomarker Levels

Improving fecal calprotectin levels involves addressing the underlying cause of inflammation. For IBD, this may include medication to reduce inflammation and maintain remission^[5]. Lifestyle modifications such as a balanced diet and stress management can also support overall gastrointestinal health^[5]. There is limited evidence supporting specific supplements for lowering calprotectin levels, but maintaining a healthy gut microbiome through probiotics may be beneficial^[5].

Importance of Tracking

Tracking fecal calprotectin levels is crucial for diagnosing and managing inflammatory gastrointestinal conditions. It helps differentiate between IBD and non-inflammatory disorders, guiding treatment decisions and reducing the need for invasive procedures like colonoscopy^[1]. Regular monitoring can also assess the effectiveness of treatments and detect early signs of relapse^[3].

Disclaimer

The information provided in this document is for educational purposes only and does not constitute medical advice. It is essential to consult with a qualified healthcare professional for any health concerns or before making any decisions related to your health or treatment.