Overview

The Entamoeba histolytica Antigen (Ag) test is used to detect the presence of Entamoeba histolytica, a parasitic protozoan that causes amoebiasis. The test helps differentiate E. histolytica from other non-pathogenic amoebas like Entamoeba dispar and Entamoeba moshkovskii.

Risk Assessment

You may need an E. histolytica Ag test if you have symptoms or risk factors such as:
Symptoms of Amoebiasis

• Diarrhea (often bloody)
• Abdominal pain
• Fever
• Nausea & vomiting
• Unexplained weight loss
• Liver abscess symptoms (right upper quadrant pain, fever, jaundice)

Risk Factors

• Travel or residence in areas with poor sanitation (South Asia, Africa, Latin America)
• Consuming contaminated food or water
• Institutional settings (prisons, mental health facilities)
• Men who have sex with men (higher transmission risk)
• Weakened immune system.

Normal Range

Negative (Normal): No Entamoeba histolytica antigen detected.

Interpretation of Results

• Positive  → E. histolytica antigen detected → Active infection
• Negative → No E. histolytica antigen detected → No active infection, but other causes of symptoms should be considered

Sample Type

• Stool Sample (preferred for detecting intestinal amoebiasis)
• Serum/Blood (used for detecting antibodies in suspected extraintestinal amoebiasis, such as liver abscess).