Blastocystis which is commonly found in the gastro-intestinal tract, has been recognized as a non-pathogenic organism for a few decades. It has a variable distribution. A high prevalence has been reported in developing countries (22.1-100%).

In developed countries, the prevalence ranges from 0.5% to 23.1%. The high prevalence noted in developing countries is related to poor hygiene and lack of safe water and food .

Blastocystis which is commonly found in the gastro-intestinal tract, has been recognized as a non-pathogenic organism for a few decades. It has a variable distribution. A high prevalence has been reported in developing countries (22.1-100%).

In developed countries, the prevalence ranges from 0.5% to 23.1%. The high prevalence noted in developing countries is related to poor hygiene and lack of safe water and food. The pathogenicity of Blastocystis is controversial because most patients carrying this parasite are asymptomatic. Several studies have considered Blastocystis sp. as a commensal micro-organism, while other results have showed the pathogenicity of the parasite.

Calprotectin (CP), a calcium-binding protein, comprises 60% of cytosolic protein found in neutrophils. Fecal calprotectin (F-CP) concentration is an indicator of neutrophil migration into the intestinal lumen and is associated with intestinal inflammation.

Inclusion Criteria:

• Patients from outpatient clinics, Sohag hospitals.

Exclusion Criteria:

• Patients taking antibiotics within the previous four weeks, and anti-parasitic drugs within the previous two weeks.

samples will be collected from outpatients with any age & sex groups from different locations (cities and villages).