'Antiphospholipid' (aPL) antibodies are a heterogenous group of autoan
tibodies that are now considered to be directed mainly to plasma prote
ins or protein-phospholipid complexes(1). Standardisation of assays fo
r anticardiolipin (aCL) antibodies and lupus anticoagulants (LA) have
been fraught with difficulty despite numerous attempts to perform this
by International Standardisation Workshops and Committees.