What are the criteria for a healthy donor for a fecal microbiota transplant (FMT)?

Healthy Donor Criteria for Fecal Microbiota Transplantation

Potential FMT donors must undergo mandatory questionnaire screening, personal interview, and laboratory testing to ensure they are between 18-60 years old with BMI 18-30 kg/m², have no recent antimicrobial use (within 3-6 months), and are free of transmissible diseases and conditions that could affect the gut microbiota. 1

Donor Selection Process

Age and BMI Requirements

• Age: 18-60 years old
• BMI: 18-30 kg/m² 1

Mandatory Screening Methods

1. Questionnaire and personal interview to identify risk factors for transmissible diseases and factors affecting gut microbiota
2. Blood screening for infectious diseases
3. Stool screening for pathogens and parasites 1

Donor Exclusion Criteria

Recent Medical History

• Receipt of antimicrobials within past 3-6 months
• Receipt of live attenuated vaccines within past 6 months
• Recent travel to tropical regions (within past 3-6 months) 1

Infectious Disease Risk Factors

• Known exposure to HIV, viral hepatitis, or tuberculosis
• Risk factors for blood-borne viruses:
  • High-risk sexual behaviors
  • Illicit drug use
  • Recent tattoo/body piercing/needlestick injury/blood transfusion/acupuncture (within 6 months) 1

Gastrointestinal Conditions

• History of IBD, IBS, chronic diarrhea, chronic constipation
• Celiac disease
• History of bowel resection or bariatric surgery
• Acute diarrhea or GI symptoms within past 2 weeks
• Family history of significant GI conditions (e.g., IBD, colorectal cancer) 1

Other Medical Conditions

• History of atopy (asthma, eosinophilic disorders)
• Systemic autoimmune conditions
• Metabolic conditions (diabetes, obesity)
• Neurological or psychiatric conditions
• Risk factors for prion disease
• Chronic pain syndromes (chronic fatigue syndrome, fibromyalgia)
• History of any malignancy 1

Medication Use

• Regular medications or medications within past 3 months:
  • Antimicrobials
  • Proton pump inhibitors
  • Immunosuppressants
  • Chemotherapy 1

Laboratory Screening Requirements

Blood Tests

• Mandatory blood screening for infectious diseases including:
  • HIV
  • Hepatitis viruses
  • EBV and CMV (especially for immunocompromised recipients) 1

Stool Tests

• Mandatory stool screening for:
  • C. difficile toxin
  • Parasites (common findings include Dientamoeba fragilis, Blastocystis hominis, Giardia) 1, 2
  • Pathogenic bacteria
  • Viruses

Practical Considerations

Donor Recruitment Challenges

• Only approximately 10% of potential donors ultimately qualify as suitable donors 2
• Common reasons for exclusion:
  • Unwillingness to meet donation frequency/duration requirements
  • Asymptomatic gastrointestinal parasites
  • Medical comorbidities 2

Donor Source Recommendations

• Both related and unrelated donors are acceptable
• When possible, FMT is best sourced from a centralized stool bank using healthy unrelated donors 1

Special Recipient Considerations

• For immunosuppressed recipients at risk of severe infection if exposed to EBV or CMV, only use donors negative for these viruses 1
• FMT should be avoided in recipients with anaphylactic food allergies 1

Follow-up Requirements

• For centers using fresh FMT, donors should complete a repeat health questionnaire at each donation
• Regular repetition of laboratory screening is required to ensure ongoing donor suitability 1

The strict screening process is essential to minimize the risk of transmitting infections or microbiota associated with disease vulnerability, as the long-term safety profile of FMT continues to be studied 3, 4.