Understanding the Key Players: Lansoprazole and Calprotectin
Lansoprazole is a widely prescribed medication belonging to the drug class known as proton pump inhibitors (PPIs) [1.5.4]. Its primary function is to reduce the amount of acid produced in the stomach [1.5.4]. It does this by inhibiting an enzyme system called the H+/K+ ATPase, or proton pump, located in the parietal cells of the stomach wall [1.5.2]. This action makes it effective for treating conditions like gastroesophageal reflux disease (GERD), stomach ulcers, and Zollinger-Ellison syndrome [1.5.4, 1.5.5].
Fecal calprotectin is a protein released by a type of white blood cell called a neutrophil [1.4.4]. When there is inflammation in the gastrointestinal tract, neutrophils are sent to the area, and they release calprotectin [1.4.4]. Measuring the level of this protein in a stool sample provides a non-invasive way to detect intestinal inflammation [1.4.4]. High levels are strongly associated with Inflammatory Bowel Disease (IBD), such as Crohn's disease and ulcerative colitis, but can also be caused by bacterial infections, colorectal cancer, and other inflammatory conditions [1.4.3, 1.4.5].
The Link: Can Lansoprazole Cause High Calprotectin?
Mounting evidence confirms a significant association between the use of proton pump inhibitors, including lansoprazole, and elevated fecal calprotectin levels [1.2.1, 1.3.2, 1.6.4]. One 2025 study involving 431 patients found that those with PPI prescriptions within 90 days of their test had significantly higher calprotectin levels (a median of 66 µg/g) compared to those without PPI prescriptions (a median of 23 µg/g) [1.3.4].
The exact mechanism for this is still under investigation, but it's believed that by altering the gut's pH, PPIs may lead to changes in the gut microbiome and potentially cause low-grade intestinal inflammation, which is then detected by the calprotectin test [1.3.1, 1.4.2]. This creates a diagnostic challenge, as an elevated result could be due to the medication itself rather than a primary inflammatory bowel disease [1.3.7]. This may lead to unnecessary and invasive investigations like colonoscopies if the medication effect is not considered [1.3.6, 1.8.3].
Interpreting Calprotectin Results for PPI Users
Due to this known interaction, clinicians must consider a patient's medication history when interpreting calprotectin results [1.3.7].
- Low Levels (<50 µg/g): Generally indicates no significant intestinal inflammation [1.7.2].
- Borderline Levels (50-120 µg/g): This range is ambiguous and could represent mild inflammation from various sources, including PPI use [1.7.2].
- High Levels (>120 µg/g): Suggestive of an active inflammatory process [1.7.2]. However, in a patient on lansoprazole, the level must be interpreted with caution. A 2025 study noted that patients on both PPIs and NSAIDs had even higher levels [1.3.4].
For patients with borderline or moderately elevated results, guidelines often suggest stopping the PPI for a period of 2 to 4 weeks (if clinically safe to do so) and then repeating the test [1.8.3, 1.8.4]. If the level normalizes after stopping the medication, the elevation was likely drug-induced. If it remains high, further investigation for underlying conditions like IBD is warranted [1.8.3]. Patients should never stop taking a prescribed medication without consulting their doctor [1.8.1].
Comparison of Factors Causing Elevated Calprotectin
| Cause | Typical Calprotectin Level | Notes |
|---|---|---|
| Inflammatory Bowel Disease (IBD) | Often very high (>250 µg/g) [1.4.5] | Levels correlate with disease activity [1.4.5]. |
| Proton Pump Inhibitors (e.g., Lansoprazole) | Mild to moderate elevation (e.g., median around 66 µg/g in one study) [1.3.4] | Can be a confounding factor in diagnosis [1.6.4]. |
| NSAIDs (e.g., Ibuprofen, Aspirin) | Mild to moderate elevation [1.4.7, 1.6.6] | Often causes irritation of the gut lining [1.4.7]. |
| Bacterial/Parasitic Infections | Can be very high [1.4.4] | Level typically returns to normal after the infection resolves [1.7.3]. |
| Colorectal Cancer | Can be elevated [1.4.4] | Calprotectin is not a primary diagnostic tool for cancer but an indicator of inflammation [1.4.7]. |
| Irritable Bowel Syndrome (IBS) | Usually normal (<50 µg/g), but can be borderline [1.4.7] | Used to differentiate from IBD [1.4.3]. |
Conclusion: A Key Consideration in Digestive Health Diagnostics
Yes, lansoprazole and other PPIs can cause high calprotectin levels. This is a crucial piece of information for both patients and healthcare providers. The use of these common medications can mimic the signs of intestinal inflammation, potentially leading to unnecessary procedures. When a fecal calprotectin test is ordered, a thorough review of medications, including over-the-counter PPIs, is essential for accurate interpretation. In many cases of moderately elevated levels, a physician-supervised discontinuation of the PPI followed by a re-test can clarify the source of the elevation and ensure the patient receives the most appropriate care path, avoiding invasive tests when they are not needed [1.8.3, 1.8.6].
Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult with a qualified healthcare professional for any health concerns or before making any decisions related to your health or treatment. Authoritative Link
