Test Directory

• Babesia microti IgG
• Babesia microti IgM

This test is a screening assay for Babesia microti infection or exposure. Serological testing for antibodies to Babesia microti (B. microti) can provide evidence to support a diagnosis of babesiosis. Serology should not be used for routine diagnosis of acute babesiosis, as it is difficult to distinguish active from past infection using serology alone. A B. microti IgG antibody titer of greater than or equal to 1:1024 or the presence of B. microti IgM antibody are suggestive of active or recent B. microti infection, while a 4-fold rise in Babesia IgG antibody in sera from the time of acute illness to the time of convalescence confirms the diagnosis. Individuals positive for B. microti antibodies should have confirmatory testing performed by PCR or peripheral blood smear before treatment is considered. The diagnosis of acute babesiosis cannot be confirmed solely by the presence of Babesia antibody in a serum sample collected at a single time point. Babesiosis coinfection should be considered in Lyme disease patients with severe illness, in those whose symptoms are unlikely to be explained by B. burgdorferi infection alone, or in those who do not respond well to standard antibiotic therapy for Lyme disease.

Specimen Type: Serum

Collection Container: Gold Top, Serum Separator

Alternate Collection Container: Red Top, Plain

Desired Specimen Volume: 1 mL

1. Collect a gold top, serum separator tube via venipuncture.

1. Separate serum from cells.
2. Transfer 1 mL of serum to a clear aliquot tube (screw cap).

Transport to the laboratory refrigerated. 

• Extensive hemolysis
• Lipemia
• Clotted specimen
• Quantity not sufficient for analysis
• Leaking or broken tube
• Frozen gel-barrier tube

See patient report.

The diagnosis of acute babesiosis cannot be confirmed solely by the presence of Babesia antibody in a serum sample collected at a single time point. Antibody detection by serologic testing can provide supportive evidence for the diagnosis of babesiosis but does not reliably distinguish between active and prior infection.