Cardiolipin antibodies are a type of autoantibody that targets cardiolipin, a phospholipid found in the membranes of mitochondria and other cellular structures. These antibodies are associated with various autoimmune conditions, particularly antiphospholipid syndrome (APS), which can lead to an increased risk of blood clots.

The cardiolipin antibodies panel typically consists of testing for three subclasses of immunoglobulins (antibodies): IgG, IgA, and IgM. Each subclass may be separately measured because their presence and levels can provide different insights into the potential autoimmune disorder.

• IgG antibodies against cardiolipin are often the most commonly tested subclass. Elevated levels of IgG cardiolipin antibodies are strongly associated with antiphospholipid syndrome (APS), which increases the risk of blood clots and other complications.
• IgM antibodies against cardiolipin are also significant, especially if they are detected along with IgG antibodies. IgM antibodies may indicate more recent or acute immune responses and can also be associated with APS.
• IgA antibodies against cardiolipin are less commonly tested but may be relevant in some cases, particularly when IgA-mediated autoimmune responses are suspected.

The presence and levels of cardiolipin antibodies, especially in combination with other clinical symptoms and test results, can aid in the diagnosis and management of autoimmune disorders like antiphospholipid syndrome.