Test: Babesia IFA
In North America, babesiosis is most commonly caused by the protozoan Babesia microti. Historically, diagnosis was made by the demonstration of characteristic intra-erythrocytic inclusions in thin-smear preparations of patient peripheral blood samples. However, the IFA test is more sensitive for detecting infected individuals with very low levels of parasitemia (such as asymptomatic blood donors in transfusion-associated cases) and for diagnosis after infection is cleared by therapy.
The Babesia microti IgG IFA tests for the presence of human IgG class antibodies against Babesia in patient serum and plasma samples. Babesia microti infected hamster erythrocytes are fixed on 12 well slides and incubated with diluted patient samples. If the sample is positive, the attached antibodies are stained with fluorescein-labeled anti-human antibodies and can be visualized using a fluorescent microscope.