Anti-phospholipid syndrome (APS) is also known as antiphospholipid syndrome. This is a syndrome whose clinical manifestations are mainly embolism, causing recurrent miscarriages in women. The cause of the disease is due to the immune system producing antibodies against phospholipids or against phospholipid-binding protein antigenic determinants. This is also a syndrome belonging to autoimmune diseases.

Antiphospholipid antibodies (APLs) are present in 60% of people with lupus and help confirm the diagnosis. A positive result is also used to determine risk for monitoring and prophylactic treatment in women with lupus. A limitation of the test is that APLs are also present in people without lupus.