Laboratory Testing for Mucositis
For patients presenting with mucositis, baseline laboratory testing should include temperature, blood pressure, heart rate, complete blood count (CBC), comprehensive metabolic panel (CMP), and C-reactive protein (CRP) to assess for infection, dehydration, and systemic inflammation. 1
Essential Baseline Laboratory Tests
When mucositis is suspected or confirmed, the following laboratory workup is recommended:
- Complete blood count (CBC) to detect leukocytosis (suggesting infection), neutropenia (increasing infection risk), or anemia 1
- Comprehensive metabolic panel including electrolytes (sodium, potassium, chloride, bicarbonate), renal function (BUN, creatinine), and glucose to identify dehydration and metabolic derangements 1
- C-reactive protein (CRP) as a marker of systemic inflammation 1
- Thyroid-stimulating hormone (TSH) particularly in patients receiving immune checkpoint inhibitors, as thyroid dysfunction can contribute to gastrointestinal symptoms 1
Additional Testing for Severe or Persistent Mucositis
For patients with grade 3-4 mucositis or those with persistent painful symptoms, additional infectious workup is warranted:
- Viral testing including HSV (herpes simplex virus) and CMV (cytomegalovirus) swabs or serology, especially in immunocompromised patients with persistent painful mucositis 1
- Fungal cultures if extensive candidiasis is suspected 1
- Blood cultures if fever or signs of sepsis are present 1
The British Society of Gastroenterology specifically recommends excluding HSV, CMV, and extensive candidiasis in patients with persistent painful mucositis 1. These infections can complicate mucositis and require specific antimicrobial therapy beyond supportive care.
Gastrointestinal Mucositis-Specific Testing
For patients with gastrointestinal mucositis presenting with diarrhea or colitis symptoms, stool studies are essential:
- Stool culture for bacterial pathogens (Salmonella, Shigella, Campylobacter, E. coli) 1
- Clostridioides difficile testing (toxin assay or PCR) 1
- Stool for ova and parasites if travel history or endemic exposure exists 1
- Fecal inflammatory markers including lactoferrin (for patient stratification to determine who needs urgent endoscopy) and calprotectin (to follow disease activity) 1
Monitoring Parameters During Treatment
Serial laboratory monitoring should include:
- Repeated assessment of CBC, CMP, and CRP to monitor response to treatment and detect complications 1
- Nutritional markers including albumin to assess nutritional status, as malnutrition is a significant risk factor for severe mucositis 1
- Fecal calprotectin levels (target ≤116 mg/g) can guide decisions on when to stop biologic treatment in immune checkpoint inhibitor-related colitis and when to resume therapy 1
Important Clinical Context
The laboratory workup should be tailored to the clinical presentation:
- For oral mucositis alone without systemic symptoms, baseline vital signs and CBC/CMP may suffice initially 1
- For severe mucositis with fever, blood cultures and infectious workup become critical 1
- For gastrointestinal mucositis with diarrhea, comprehensive stool studies are mandatory before initiating immunosuppressive therapy 1
Common pitfalls to avoid:
- Do not delay infectious workup in immunocompromised patients with persistent symptoms, as HSV and CMV can significantly worsen mucositis outcomes 1
- Do not assume all diarrhea in cancer patients is treatment-related; infectious causes must be excluded first 1
- Normal inflammatory markers do not exclude significant mucositis, as clinical assessment remains paramount 1