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.

Basophils absolute measures the count of basophil white blood cells per microlitre of blood. Basophils are the rarest white blood cell type — normally making up less than 1% of all WBCs — and a result of 0.0 is entirely normal. The reference range is 0–0.2 ×10³/µL (0–200 cells/µL). A mildly elevated count (above 0.2) may reflect allergic reactions, inflammation, or thyroid conditions. Markedly elevated basophils (above 1.0) warrant clinical evaluation to exclude a myeloproliferative disorder such as CML. Low or zero basophils without symptoms require no action.

What Are Basophils?

Basophils are a type of white blood cell (leukocyte) that plays a key role in your immune system, particularly in defending your body against allergens, pathogens, and parasites. Despite their small numbers—they make up less than 1% of your white blood cells—basophils are essential in managing allergic reactions and inflammatory responses.

Characteristics of Basophils

• Short Life Span: Basophils typically live only one to two days in the bloodstream.
• Mononuclear Cells: They have a single, round nucleus.
• Granulocytes: Basophils are part of the granulocyte family, meaning they contain granules—small particles filled with enzymes like histamine and heparin. These enzymes are released during immune responses, particularly allergic reactions.
• Unique to Basophils: Basophils are the only white blood cells that contain histamine, a key player in allergic reactions.

Basophils are not a primary focus in synovial fluid analysis, and their presence in synovial fluid is typically not a key diagnostic marker for joint-related conditions. Instead, the analysis primarily concentrates on more common white blood cell types to assess joint health and inflammation.