Interferon-Alpha Test: Antiviral Immune Activity and Inflammation Meaning
An interferon-alpha test looks at one part of the body’s early antiviral defense system. Interferon-alpha, usually written IFN-α, is a family of type I...
Interferon-Gamma Test: Immune Activation, Infection Response, and T-Cell Activity
An interferon-gamma test can mean several different laboratory procedures, and the distinction changes the interpretation. Interferon-gamma, or IFN-γ, is a cytokine made mainly by...
Interleukin-1 Beta (IL-1β) Test: Inflammation, Immune Activation, and Autoinflammatory Disease
An interleukin-1 beta test measures a powerful inflammatory cytokine, but it is not a general-purpose test that can diagnose inflammation by itself. Interleukin-1 beta,...
Interleukin-2 (IL-2) Test: T-Cell Activation, Immune Response, and Meaning
An interleukin-2 (IL-2) test measures a cytokine that activated T cells release to coordinate immune-cell growth, survival, and regulation. Although IL-2 is often described...
Interleukin-4 (IL-4) Test: Allergy, Th2 Immune Response, and Immune Signaling
An interleukin-4 (IL-4) test measures a cytokine central to type 2 immunity, the immune program involved in defense against parasites, tissue repair, antibody class...
Interleukin-5 (IL-5) Test: Eosinophilic Inflammation, Allergy, Asthma, and Meaning
An interleukin-5 (IL-5) test measures a cytokine that promotes eosinophil development, survival, activation, and movement from bone marrow into blood and tissues. IL-5 is...
Interleukin-6 (IL-6) Test: High Levels, Inflammation, Cytokine Activity, and Immune Response
An interleukin-6 (IL-6) test measures a rapidly changing cytokine involved in infection defense, inflammation, antibody responses, blood-cell production, metabolism, and tissue repair. IL-6 can...
Interleukin-8 (IL-8) Test: Neutrophil Inflammation, Infection Response, and Meaning
An interleukin-8 (IL-8) test measures a chemokine—also named CXCL8—that directs neutrophils toward infection, tissue injury, and other inflammatory signals. IL-8 can rise quickly when...
Interleukin-10 (IL-10) Test: Immune Regulation, Inflammation Control, and Meaning
An interleukin-10 test measures a cytokine that helps prevent an immune response from causing unnecessary damage. Interleukin-10, abbreviated IL-10, is often described as anti-inflammatory,...
Interleukin-12 (IL-12) Test: Immune Activation, T-Cell Response, and Meaning
An interleukin-12 test measures a cytokine that connects early innate immune sensing with a strong cellular immune response. Interleukin-12, or IL-12, is produced mainly...
Interleukin-17 (IL-17) Test: Autoimmune Inflammation, Th17 Response, and Meaning
An interleukin-17 test measures a cytokine involved in barrier defense, neutrophil recruitment, and several immune-mediated inflammatory diseases. The name “IL-17” usually refers to IL-17A,...
Interleukin-18 (IL-18) Test: Inflammation, Macrophage Activation, and Hyperinflammation
An interleukin-18 test measures an inflammasome-related cytokine that can become markedly elevated in several hyperinflammatory disorders. Interleukin-18, abbreviated IL-18, is made as an inactive...
Interleukin-23 (IL-23) Test: Autoimmune Inflammation, Th17 Pathway, and Meaning
An interleukin-23 (IL-23) test measures a cytokine involved in type 17 immunity, a defense system that helps protect skin and mucosal surfaces from selected...
Lymphocyte Proliferation Test: T-Cell Function, Mitogen Response, and Immune Deficiency
A lymphocyte proliferation test evaluates whether living lymphocytes—especially T cells—can activate and divide after stimulation in the laboratory. It is a functional test, not...
Lymphocyte Subset Panel: T Cells, B Cells, NK Cells, CD4/CD8 Ratio, and Immune Function
A lymphocyte subset panel uses flow cytometry to count major immune-cell populations in blood, usually CD3 T cells, CD4 helper T cells, CD8 cytotoxic...
Macrophage Activation Syndrome Blood Test Panel: Ferritin, IL-18, Cytokines, and Hyperinflammation
A macrophage activation syndrome blood test panel is not one single laboratory test. It is a coordinated set of urgent studies used when clinicians...
Natural Killer Cell Count Test: NK Cells, Immune Function, and Viral Defense
A natural killer cell count test measures the number and percentage of circulating NK cells, usually by flow cytometry. Most laboratories identify NK cells...
Natural Killer Cell Function Test: NK Cell Activity, Immune Defense, and Meaning
A natural killer cell function test evaluates how well NK cells respond to stimulation or damage target cells in the laboratory. Depending on the...
Neutrophil Oxidative Burst Test: Chronic Granulomatous Disease Screening and Neutrophil Function
A neutrophil oxidative burst test measures whether neutrophils can generate reactive oxygen species after stimulation. The most widely used method is the dihydrorhodamine 123,...
Regulatory T-Cell Test: Tregs, Immune Tolerance, Autoimmunity, and Meaning
A regulatory T-cell test uses flow cytometry to estimate the number or percentage of circulating Tregs, most often within the CD4 T-cell population. Clinical...