Referral guideline – Dientamoeba fragilis and blastocystis SPP


Dientamoeba Fragilis and Blastocystis spp are protozoa that are often tested for within the stool PCR assay. Clinicians should interpret positive PCR to these protozoa with caution as they are very often colonising flora with limited clinical significance, rather than gastrointestinal pathogens.

Gastrointestinal symptoms are often falsely attributed to Dientamoeba Fragilis and Blastocystis spp leading to increased medical consultations, unnecessary use of antimicrobials and anxiety for families.

GP management

If patient is PCR +ve to Dientamoeba Fragilis or Blastocystis spp, but has no gastrointestinal symptoms: do not treat, and do not repeat stool testing.

If the patient is symptomatic and is PCR +ve Dietamoeba Fragilis or Blastocystis spp., look for other causes of symptoms.

When to refer

Consider referral to a general paediatrician if there is no other explanation for ongoing gastrointestinal symptoms.

Essential referral info

  • Current symptoms and history of this, including whether any treatment has been given
  • Stool results
  • Other pathology if performed
  • Patient details
  • Medicare number
  • Parent/carer name and contact details
  • Referring clinician details (name, contact details, provider number, date and length of referral)

Helpful referral info

  • Past medical and surgical history
  • Allergies
  • Growth parameters
  • Family history of GI problems

Parent service

Gastroenterology, Hepatology and Liver Transplant

Contact details

Hospital Switchboard
(Ask for Gastroenterology On-call Registrar)
t: 07 3068 1111


Stool Colour Card