From the Guidelines
For monitoring ulcerative colitis or Crohn's disease, I recommend regular laboratory testing including complete blood count (CBC), comprehensive metabolic panel (CMP), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and fecal calprotectin, as suggested by the most recent guidelines 1. This approach is based on the latest evidence from the AGA clinical practice guideline on the role of biomarkers for the management of ulcerative colitis, which provides conditional recommendations for the use of biomarkers in monitoring disease activity and guiding treatment decisions 1. The recommended tests are:
- CBC to detect anemia and inflammation through white blood cell counts
- CMP to assess liver and kidney function, which can be affected by both the disease and medications
- CRP and ESR as inflammatory markers to track disease activity
- Fecal calprotectin to specifically measure intestinal inflammation and correlate with endoscopic findings Additional monitoring may be needed for patients on specific medications, such as:
- Thiopurines (azathioprine, 6-MP) requiring TPMT testing before initiation and regular CBC and liver function tests
- Biologics needing tuberculosis screening before starting and periodic CBC
- Methotrexate requiring liver function tests and CBC Vitamin B12, folate, iron studies, and vitamin D levels should also be checked periodically to monitor for common nutritional deficiencies. The frequency of testing depends on disease activity, medication regimen, and individual patient factors, but generally ranges from every 3-6 months during stable periods to more frequently during flares, as supported by the guidelines 1. It is essential to consider the certainty of evidence and the strength of recommendations when making clinical decisions, and to prioritize the most recent and highest-quality studies, such as those published in 2023 1.
From the Research
Laboratory Tests for Monitoring Ulcerative Colitis and Crohn's Disease
To monitor ulcerative colitis and Crohn's disease, several laboratory tests can be ordered, including:
- C-reactive protein (CRP) levels, which can indicate inflammatory activity 2, 3
- Fecal calprotectin (FC) levels, which can also indicate inflammatory activity 3
- Erythrocyte sedimentation rate (ESR), which can be elevated in patients with Crohn's disease and ulcerative colitis 2
- Complete blood count (CBC) to check for anemia, which is a common complication of inflammatory bowel disease 4, 5
- Iron laboratory tests to check for iron deficiency anemia, which is highly prevalent in patients with Crohn's disease and ulcerative colitis 4
- Vitamin B12 and folic acid levels to check for deficiencies, which can contribute to anemia 4
Disease Activity Assessment
Disease activity can be assessed using clinical activity indices, which are still commonly used for both Crohn's disease and ulcerative colitis 6. Endoscopic evaluation with ileocolonoscopy is the gold standard for monitoring disease activity, but it is invasive, costly, and time-consuming 3. Imaging procedures, such as computed tomography enterography (CTE), can also be used to assess disease activity, especially in Crohn's disease 6.
Anemia Management
Anemia is a common complication of inflammatory bowel disease, and its management is important for patient care 4, 5. The differential diagnosis between iron deficiency anemia and anemia of chronic disease can be made based on clinical data and routine laboratory tests 4. Treatment of anemia should be tailored to the underlying cause, and distinguishing between the different types of anemia is crucial for appropriate management 5.