Test Catalog

Test ID: BART    
Bartonella Antibody Panel, IgG and IgM, Serum

Useful For Suggests clinical disorders or settings where the test may be helpful

Diagnosis of Bartonella infection, especially in the context of a cat scratch

Testing Algorithm Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Bartonella henselae and Bartonella quintana are small, rod-shaped, pleomorphic, Gram-negative bacteria. The human body louse (Pediculus humanis) is the proposed vector for B quintana. No animal reservoir has been determined for B quintana. The domestic cat is believed to be both a reservoir and vector for B henselae. Cats may infect humans directly through scratches, bites, or licks; or indirectly through an arthropod vector. Humans remain the only host in which Bartonella infection leads to significant disease.


The sight of entry for Bartonella is through openings in the skin. Microscopically, Bartonella lesions appear as rounded aggregates that proliferate rapidly. These aggregates are masses of Bartonella bacteria. Warthin-Starry staining has shown that Bartonella organisms can be present within the vacuoles of endothelial cells, in macrophages, and between cells in areas of necrosis. Occasionally organisms are seen in the lumens of vessels. While cutaneous lesions are common, disseminated tissue infection by Bartonella has been seen in the blood, lymph nodes, spleen, liver, bone marrow, and heart. B henselae has been associated with cat scratch disease (CSD), peliosis hepatitis (PH), bacillary angiomatosis (BA), and endocarditis. B quintana has been associated with trench fever, BA, and endocarditis. BA is a vascular proliferative disease usually involving the skin and regional lymph nodes.


CSD begins as a cutaneous papule or pustule that usually develops within a week after an animal contact. Regional lymphadenopathy follows and is the predominant clinical feature of CSD. Trench fever, which was a significant problem during World War I and World War II, is characterized by a relapsing fever and severe pain in the shins. PH and febrile bacteremia syndrome are both syndromes that have afflicted patients with AIDS and patients who are immunocompromised. While trench fever and CSD are usually self-limiting illnesses, the other Bartonella-associated diseases can be life-threatening.


Interest in B quintana and B henselae has recently increased since its increased prevalence in patients with AIDS, in transplant patients, and those with suppressed immunity.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

Bartonella henselae

IgG: <1:128

IgM: <1:20


Bartonella quintana

IgG: <1:128

IgM: <1:20

Interpretation Provides information to assist in interpretation of the test results

A positive immunofluorescence assay (IFA) IgM (titer >1:20) suggests a current infection with either Bartonella henselae or Bartonella quintana.


A positive IgG (titer >1:128) suggests a current or previous infection. Increases in IgG titers in serial specimens suggest active infection.


Normal serum specimens usually have an IgG titer of less than 1:128. However, 5% to 10% of healthy controls exhibit a B henselae and B quintana titer of 1:128. Sera from healthy volunteers rarely show titers of 1:256 or greater. IgM titers in normal serum are typically less than 1:20. IgM titers at 1:20 or greater have not been seen in the normal population.


Molecular testing of tissue for Bartonella species nucleic acid is recommended in cases of suspected endocarditis.

Clinical Reference Recommendations for in-depth reading of a clinical nature

1. Rodino KG, Stone E, Saleh OA, Theel ES: The Brief Case: Bartonella henselae endocarditis-a case of delayed diagnosis. J Clin Microbiol. 2019 Aug 26;57(9). e00114-19. doi: 10.1128/JCM.00114-19

2. Wolf LA, Cherry NA, Maggi RG, Breitschwerdt EB: In pursuit of a stealth pathogen: Laboratory diagnosis of bartonellosis. Clin Micro News. 2014;36(5):33-39

Special Instructions Library of PDFs including pertinent information and forms related to the test