Echinococcus IgG Antibody Test in California

What this test measures

Echinococcus is a genus of tapeworm. The adult worms live in the intestines of animals such as dogs, and their eggs can be passed in feces. People can become infected by accidentally swallowing eggs, after which the parasite can form cysts in organs such as the liver and lungs. This condition is called echinococcosis, and it may stay silent for years before causing symptoms.

The test measures IgG antibodies against Echinococcus in a blood sample. IgG antibodies can appear once the immune system recognizes the parasite, so the assay can support a diagnosis when imaging or exposure history suggests infection. Results are reported as detected or not detected, sometimes with a level. Because antibody tests can have limitations, they are used together with imaging and other clinical information.

The test may be ordered for people with suspicious cysts found on imaging, for those with a known exposure history, and during follow-up of a diagnosed infection. A negative result does not always rule out infection, and a positive result does not reveal where the parasite is or how long it has been present. Clinicians interpret the findings with the full clinical picture.