Myeloperoxidase Antibody (MPO) Blood Test

What is the purpose of this test?

Order this Myeloperoxidase (MPO) Antibody Blood Test to detect MPO antibodies in the blood and help screen for vasculitis. Myeloperoxidase (MPO) is an enzyme released by white blood cells that measure disease activity from the luminal aspect of the arterial wall. When the artery wall is damaged or inflamed, MPO is released by white blood cells called macrophages. MPO then oxidizes LDL (bad cholesterol), making it atherogenic, which then oxidizes HDL (good cholesterol), rendering it dysfunctional. This results in inflammation linked to plaque formation in the artery wall, also known as vasculitis. 

While routine lipid panels play a vital role in assessing an individual's risk for cardiovascular disease, they do not provide information on the damaging inflammation in the walls of the arteries. As a result, nearly half of all heart attacks occur in individuals with "normal" cholesterol levels because of vascular inflammation (vasculitis), not cholesterol.

It is also important to note that:

• Individuals with elevated MPO levels are more than 2x as likely to experience cardiovascular mortality.
• Elevated MPO levels indicate a high risk of heart disease in subgroups with cholesterol results associated with low risk.
• Elevated MPO levels are not a result of chronic infections or rheumatologic disorders since MPO in the blood is a specific marker of vascular inflammation and vulnerable plaque.

When should I order a Myeloperoxidase (MPO) Antibody Blood Test?

Individuals may order this test if they have experienced symptoms related to vasculitis. Common signs or symptoms of vasculitis may include: 

• Joint, muscle, and abdominal pain
• Swelling
• Fever
• Abnormal heart rate
• Shortness of breath
• Fatigue and headaches
• Rashes or ulcers
• Weight loss