Babesia microti Antibodies, (IgG/IgM) with Reflex to Titers

Babesia microti IgG and IgM Antibodies, Human Babesiosis, Babesiosis IgG & IgM, Babes

Test Codes

EPIC: LAB1232284, Beaker: B.MICROTI AB, Quest: 16194

Department

Send Outs

Specimen Collection Criteria

Collect (preferred specimen): One Gold-top SST tube.
Also acceptable: One plain Red-top tube.

Physician Office/Draw Specimen Preparation

Let specimen clot 30-60 minutes then centrifuge to separate serum from cells. Transfer serum to a plastic transport tube and refrigerate at (2-8°C or 36-46°F).

Preparation for Courier Transport

Transport: 1.0 mL serum, refrigerated at (2-8°C or 36-46°F) (Minimum: 0.2 mL)

Rejection Criteria

Specimens not collected and processed as indicated.

In-Lab Processing

Let specimen clot 30-60 minutes then centrifuge to separate serum from cells. Transfer serum to a plastic transport tube and refrigerate at (2-8°C or 36-46°F).

Transport: 1.0 mL serum, refrigerated at (2-8°C or 36-46°F). (Minimum: 0.2 mL)

Storage

Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): 72 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): 30 days

Specimen Storage in Department Prior to Disposal:

Specimen retention time is determined by the policy of the reference laboratory. Contact the Send Outs Laboratory with any questions.

Laboratory

Sent to Quest Diagnostics, Wood Dale, IL.

Performed

Monday, Wednesday – Saturday.
Results available in 2-4 days.

Reference Range

Babesia microti Antibodies (IgG), Screen:  Not detected.
Babesia microti Antibodies (IgM), Screen:  Not detected.
Babesia microti Antibodies (IgG), Titer:  <1:64
Babesia microti Antibodies (IgM), Titer:  <1:20

Test Methodology

Immunofluorescence Assay (IFA)

Clinical Utility

Babesia microti Antibodies (IgG, IgM), with Reflex to Titers – This test is for the detection of IgG and IgM antibodies against Babesia microti to aid in the diagnosis of Babesiosis. Babesiosis is a tickborne disease caused by transmission of the protozoa via the bite of an infected tick. B. microti is most common in the northern and upper Midwestern United States.

Testing for B. microti is based on a clinical evaluation and risk of tick exposure with consideration to the geographic region. Symptoms may be nonspecific, including headache, fever/chills, malaise, myalgia, and gastrointestinal symptoms. Infection can have similarities with other tickborne illnesses with overlapping vectors, geographic endemicity, and similar clinical signs and symptoms, including Anaplasma spp, Ehrlichia spp, and Borrelia burgdorferi (Lyme disease).

Negative results can occur early in infection. Nucleic acid amplification tests are the preferred method for diagnosis during acute infection. Seroconversion or a four-fold increase between acute and convalescent sera can be used to support a diagnosis. The presence of IgG alone may indicate past infection, and IgM may persist for many months after infection has resolved. Antibody levels may remain elevated for several years after acute illness. Other less common Babesia species in different geographic regions have been identified to infect humans, such as B. duncani and B. divergens. The extent of cross-reactivity between Babesia species is variable and may not be detected by this assay. Therefore, interpretation of serologic results is done in the context of pertinent clinical picture, including timing from symptom onset.

Reference

1. Tickborne Diseases of the United States. A Reference Manual for Healthcare Providers, Sixth Edition, 2022. Centers for Disease Control and Prevention.
2. Clinical Testing and Diagnosis for Ehrlichiosis. Centers for Disease Control and Prevention. Last updated May 15, 2024. https://www.cdc.gov/ehrlichiosis/hcp/diagnosis-testing/index.html⁠⁠⁠⁠⁠⁠⁠
3. Krause, PJ. et al. Clinical Practice Guidelines by the Infectious Diseases Society of America (IDSA): 2020 Guideline on Diagnosis and Management of Babesiosis. Clin Infect Dis. 2021 Jan 27;72(2):e49-e64. doi: 10.1093/cid/ ciaa1216.

CPT Codes

86753x2

Contacts

Last Updated

1/29/2026