Cathepsin G Antibody, Serum

What This Test Measures

Cathepsin G is an enzyme stored in granules of neutrophils, a type of white blood cell involved in fighting infection and in inflammation. This test detects antibodies in your blood that target cathepsin G. The presence of such antibodies can be a marker that your immune system is reacting against components of your own white blood cells.

Why Your Doctor May Order It

Your healthcare provider may order this test when evaluating certain inflammatory or immune-related conditions, particularly those affecting blood vessels or the lungs. It is often considered alongside other antibody tests to build a fuller picture of what is happening in your immune system. The result is interpreted together with your symptoms, physical exam, and other laboratory findings.

How the Sample Is Collected

The test is performed on serum, the clear liquid part of blood that remains after the blood has clotted. A healthcare professional collects a standard blood sample from a vein in your arm. You generally do not need special preparation unless your provider gives other instructions.

Understanding Your Results

Results are typically reported as positive or negative, or with a measured level, depending on the laboratory. A positive result means these antibodies were detected, but it does not by itself confirm a specific diagnosis. Your provider will interpret the result in the context of your overall health picture and may order additional testing.