CHAPTER 05 · DIAGNOSIS
Diagnostic Process
Getting diagnosed with UC involves a few different tests. Here’s what each one checks for — and how doctors measure how active the disease is.
At the beginning of the diagnostic process, your doctor will take a full medical history, including questions about your and your family’s general health, as well as your current symptoms. A physical examination and several other diagnostic tests and procedures usually follow the interview with your doctor.
Diagnosing Tests & Procedures
💩 Stool Sample
What it checks
- Checks for infectious diseases (bacteria, viruses, parasites)
- Measures fecal calprotectin levels (indicates level of inflammation)
🩸 Blood Work
What it checks
- Complete blood count (CBC) and differential
- Checks for signs of infection and anemia among others
- Nutritional status (iron, ferritin, vitamin B12, folic acid) — also assesses for anemia and malnutrition often found in IBDs
- Tests for increased inflammatory markers (ESR, CRP, leukocytosis)
- P-ANCA and ASCA antibody tests — these can help your doctor distinguish UC from other inflammatory bowel diseases
🔬 Endoscopy
What it involves
- Gastroscopy with biopsies (tissue samples)
- Colonoscopy with biopsies (tissue samples)
🖼️ Imaging
What it involves
- For instance: computed tomography (CT) scan, magnetic resonance imaging (MRI), magnetic resonance enterography (MRE), video capsule endoscopy (PillCam), or ultrasound
- Imaging helps to further assess the severity of intestinal inflammation and the swelling of different layers of the colon
Good to know
You probably won’t need every single test — your doctor will pick the ones that fit your symptoms. Each test gives a different piece of the puzzle.
PUCAI Score
Once ulcerative colitis is diagnosed, your doctor might calculate a Pediatric Ulcerative Colitis Activity Index (PUCAI score) to assess the severity of any flare-up and monitor disease activity. The PUCAI score is grouped into four severity levels:
The four severity levels:
Don’t try to score yourself
Your doctor uses the PUCAI score together with exam findings, lab results, and the bigger picture of how you’re doing to guide your care. The factors below show what they look at — they’re not a self-test.
Factors considered in the PUCAI score
Abdominal pain
How much pain you have, and whether you can ignore it or not.
Rectal bleeding
Whether you see blood in your stools, how often, and how much.
Stool consistency
Whether your stools are formed, partly formed, or completely unformed.
Stool frequency
How many times you go to the bathroom each day.
Bathroom visits at night
Whether bathroom trips wake you up at night.
Activity level
How much your symptoms get in the way of your normal day.
If any symptom is worrying you, contact your medical team.
TeenHealthInsight is a health education resource — not a substitute for medical advice, diagnosis, or treatment from your doctor or gastroenterologist.