HLA-B27 is a specific protein (human leukocyte antigen B27) found on the surface of white blood cells. Flow cytometry is a technique used to analyze the physical and chemical characteristics of particles, typically cells, as they flow in a fluid stream through a beam of light.

HLA-B27 flow cytometry is a diagnostic test used to detect the presence of HLA-B27 protein on the surface of white blood cells. This test is primarily used in the diagnosis of conditions such as ankylosing spondylitis, reactive arthritis, and other autoimmune disorders, as the presence of HLA-B27 is associated with an increased risk of developing these conditions.

During the test, a blood sample is taken from the patient, and the white blood cells are labeled with fluorescent antibodies that specifically bind to the HLA-B27 protein. The labeled cells are then passed through a flow cytometer, which detects the fluorescent signal emitted by the labeled cells. The presence or absence of HLA-B27 on the surface of the white blood cells can be determined based on the intensity of the fluorescent signal.

HLA-B27 flow cytometry is an important tool in the diagnosis and management of autoimmune disorders, as it provides valuable information about the patient’s immune system and can help guide treatment decisions.