Here is a story to help illustrate how these tests work and why they are vital for diagnosis. The Story of the Silent Guard

: Diagnosis requires two positive tests 12 weeks apart.

A functional test that looks at how long it takes for your blood to clot in a test tube.

When these "Silent Guards" (the antibodies) mistakenly attack, they cause the blood to become "sticky," leading to unexpected traffic jams——in the veins or arteries. The Investigation (Detection)

An ELISA test that measures specific antibodies attacking cardiolipin, a type of phospholipid.