From the Guidelines
Beyond stool studies, ESR, and CRP, additional diagnostic tests should include complete blood count (CBC), comprehensive metabolic panel, liver function tests (LFT), magnesium, lipid profile, abdominal X-ray, and tests for infections such as Clostridium difficile, as well as serological tests for hepatitis B, tuberculosis, and other infections as indicated by patient risk factors and medical history. These tests are essential for assessing disease severity, excluding infections, and predicting poorer outcomes, as stated in the 2016 review article on acute severe ulcerative colitis 1. Key laboratory tests include:
- Full blood count (FBC) to evaluate for anemia, thrombocytosis, or leucocytosis
- Electrolyte/urea/creatinine to assess renal function and electrolyte balance
- Liver function tests (LFT) to evaluate for liver involvement
- Magnesium and lipid profile, particularly in patients considered for ciclosporin therapy, as hypomagnesemia and low serum cholesterol can decrease the seizure threshold 1
- Inflammatory markers such as CRP and ESR, although nonspecific, can help assess disease severity and monitor response to treatment Imaging studies such as abdominal X-ray can help diagnose toxic megacolon, a life-threatening complication of ulcerative colitis, characterized by a colonic diameter of >5.5 cm on abdominal X-ray in the presence of systemic toxicity 1. Endoscopic procedures, including colonoscopy with biopsies, are crucial for direct visualization of the intestinal mucosa and obtaining tissue samples for histopathological examination, as recommended in the 2021 AGA clinical practice update on diagnosis and management of immune checkpoint inhibitor colitis and hepatitis 1. Serological tests for infections such as hepatitis B, tuberculosis, and other infections should be performed based on patient risk factors and medical history, as these can impact treatment decisions and outcomes 1. Fecal calprotectin is a valuable marker of intestinal inflammation and can help differentiate between inflammatory and non-inflammatory causes of diarrhea, as discussed in the 2017 European evidence-based consensus on diagnosis and management of ulcerative colitis 1. Genetic testing for NOD2/CARD15 mutations may help identify Crohn's disease susceptibility, although this is not directly related to the initial diagnostic workup for ulcerative colitis. The combination of these laboratory, imaging, and endoscopic findings provides a complete clinical picture necessary for accurate diagnosis and appropriate treatment planning, ultimately improving patient outcomes in terms of morbidity, mortality, and quality of life.
From the Research
Diagnostic Tests for Inflammatory Bowel Disease
Besides stool studies, ESR, and CRP, the following diagnostic tests can be included:
- CT imaging of the abdomen and pelvis to assess for colitis, Crohn's disease, and other inflammatory conditions 2
- CT enteroclysis, dynamic contrast enhancement, CT angiography, and 3D imaging to evaluate the small bowel and diagnose Crohn's disease 3
- Endoscopic terminal ileum biopsies to diagnose or rule out Crohn's disease and other inflammatory conditions 4
- Abdominopelvic CT scans to identify urgent findings such as abscesses, perforations, and obstructions in patients with Crohn's disease 5
- CT enterography to noninvasively evaluate Crohn's disease and obscure gastrointestinal bleeding 6
Imaging Tests
Imaging tests such as CT scans and CT enterography can be used to:
- Evaluate the extent of disease and assess for complications such as abscesses and fistulas
- Monitor disease activity and response to treatment
- Identify alternative diagnoses and rule out other conditions
Endoscopic Tests
Endoscopic tests such as terminal ileum biopsies can be used to:
- Diagnose or rule out Crohn's disease and other inflammatory conditions
- Evaluate the severity of disease and assess for mucosal healing
- Monitor disease activity and response to treatment
Laboratory Tests
Laboratory tests such as ESR and CRP can be used to:
- Monitor disease activity and assess for inflammation
- Evaluate response to treatment and adjust therapy as needed
- Identify alternative diagnoses and rule out other conditions