What is Bartonella henselae 26 kDa – IgG?

Bartonella henselae is a bacterial species known for causing Cat Scratch Disease (CSD) as well as other systemic or chronic infections in certain individuals. It is primarily transmitted through scratches or bites from cats, but it may also be spread via fleas or ticks.

The 26 kDa – IgG test detects the presence of IgG antibodies to a 26-kilodalton (kDa) protein expressed by Bartonella henselae. IgG antibodies generally appear weeks after infection and can remain in the body for months or even years, indicating a long-term immune response.

What is Bartonella henselae 26 kDa – IgM?

Bartonella henselae is a bacterial species best known for causing Cat Scratch Disease (CSD) and can also lead to more serious or chronic infections in some individuals. It is most commonly transmitted through scratches or bites from cats, but it can also be spread through fleas or ticks.

The 26 kDa – IgM test detects IgM antibodies directed against a 26-kilodalton protein produced by Bartonella henselae. IgM is the first type of antibody the body produces in response to infection, usually appearing within 1–2 weeks after initial exposure. Because of this, a positive result may signal a recent or active infection.

What Does a Medium Result Mean?

A medium IgM result indicates a moderate level of early antibodies, which may reflect:

• An early-stage infection, where the immune response is still developing

• A waning infection, with IgM levels beginning to decline

• A borderline or nonspecific reaction, which should be interpreted carefully

Medium results are not diagnostic by themselves and should be considered alongside clinical symptoms, IgG antibody levels, and other relevant testing such as PCR (which detects bacterial DNA).

Bartonella henselae Ab, IgG is a blood test that measures the level of IgG antibodies against the bacteria Bartonella henselae, which is commonly associated with cat scratch disease. IgG antibodies are produced by the immune system as a response to a past or ongoing infection, indicating that the person has been exposed to the bacteria. A positive IgG result suggests a previous infection with Bartonella henselae and that the body has developed immunity to it, although it may also indicate a chronic or persistent infection. Typically, this test is used to help diagnose cat scratch disease, which can cause symptoms like swollen lymph nodes, fever, and fatigue, particularly in people who have had contact with cats or have been scratched or bitten by one.

Bartonella henselae Ab, IgM is a blood test marker used to detect the presence of IgM antibodies against the Bartonella henselae bacteria, which is the cause of cat scratch disease and other Bartonella-related infections. The IgM antibodies are part of the immune system's early response to an infection, and their presence usually indicates a recent or ongoing infection with Bartonella henselae. When someone has symptoms like fever, swollen lymph nodes, or a history of being scratched or bitten by a cat, this test helps diagnose Bartonella infection by confirming that the body is actively fighting the bacteria. A positive IgM result suggests a recent infection, while a negative result might indicate either no infection or a past infection where IgM antibodies have already declined.

Bartonella henselae IgG measures antibodies your immune system makes after exposure to the bacterium that causes most cases of cat-scratch disease. Results are reported as titers and must be read against your lab’s reference range: negative suggests no prior exposure, equivocal is unclear and usually merits a repeat test in 10–14 days, and positive indicates current or past exposure—on its own it does not prove active infection; a rising titer between two tests better supports a recent infection. Because IgG can persist for years and may cross-react with other Bartonella species, results should be interpreted alongside your symptoms and exam, and sometimes with additional tests (IgM or PCR), especially if illness is atypical, severe, or you’re immunocompromised. Most healthy people recover without complications; treatment decisions depend on your situation. To lower risk, promptly wash scratches or bites and use regular flea control for pets—testing healthy cats isn’t recommended.

Several species of Bartonella bacteria cause disease in people. Infection with any one of these bacteria is referred to broadly as bartonellosis, although some forms of infection also have common names (for example, cat scratch disease). 

Bartonella bacteria are spread to humans by fleas, body lice, sand flies, or contact with flea-infested animals. There is no evidence that ticks spread Bartonella infection to people. In the United States, the most common form of bartonellosis is caused by Bartonella henselae.

The Bartonella species (IgG) marker on a Bartonellosis panel plays a pivotal role in the serological diagnosis of infections caused by various Bartonella species, which include notable pathogens like Bartonella henselae and Bartonella quintana. This test specifically targets Immunoglobulin G (IgG) antibodies, which are produced by the immune system as a later response to an infection. IgG antibodies typically develop within a few weeks post-exposure and can persist for months or years, providing long-term immunity and indicating either past exposure or a chronic infection.

The Bartonella species (IgM) marker, a crucial element in the diagnostic panel for Bartonellosis, is designed to detect specific Immunoglobulin M (IgM) antibodies in the bloodstream, targeting various Bartonella species, including common pathogens like Bartonella henselae and Bartonella quintana. IgM antibodies are the initial type of antibody that the immune system produces in response to an infection. Their presence in the blood usually indicates a recent or acute infection with Bartonella, as these antibodies typically appear within a few days to a week following exposure and can remain detectable for several months thereafter.

Bartonella vinsonii, a member of the genus Bartonella, is a proteobacterium that is the causative agent of Bartonellosis. The pathogen has been isolated in immunocompetent patients with endocarditis, arthritis, neurological disease and neoplasia . From animal studies it appears that Bartonella henselae is well adapted to felines or cats while Bartonella vinsonii is well adapted to canines or dogs though each species can infect both.

The Base Excess (ECF) - Arterial marker on Labcorp's Arterial Blood Gas (ABG) Panel quantifies the amount of acid or base required to restore a liter of arterial blood to a normal pH of 7.40 at a PaCO2 of 40 mmHg and a temperature of 37°C. This value reflects the metabolic component of acid-base balance, independent of respiratory influences.

Clinical Significance

• Positive Base Excess: Indicates metabolic alkalosis, where there is an excess of base or a deficit of acid in the blood.

• Negative Base Excess: Suggests metabolic acidosis, characterized by an excess of acid or a loss of base.

What Are Basophils?

Basophils are a type of white blood cell that helps defend against allergens, pathogens, and parasites. They have a short lifespan of one to two days and play a key role in the immune response.

As granulocytes, basophils contain histamine and heparin, which regulate inflammation. Histamine widens blood vessels, triggering allergy symptoms like sneezing and a runny nose, while heparin prevents excessive blood clotting.

Basophils also interact with immunoglobulin E (IgE), working alongside mast cells to release histamine and serotonin, amplifying allergic and inflammatory responses.

Though small in number, basophils are essential for immune defense and allergic reactions.