Based on the observation that PS is expressed on the surface of mammalian apoptotic cells (Fadok et al., 1992), which annexin A5 binds with a high affinity, annexin A5 can be used in flow cytometry to detect apoptotic cells after chemotherapy (Koopman et al., 1994; Belhocine et al., 2002), cord blood to improve prediction of potency for engraftment (Duggleby et al., 2012), and detection of anti-platelet antibodies for the diagnosis of antiphospholipid syndrome (Tomer et al., 2007). This evidence concerns the gene ANXA5 and antiphospholipid syndrome.