Hello Kate
The two main tests for APS are the lupus anticoagulant, so called, which is various clotting tests, and more importantly for anti cardiolipins. They both need to be repeated at an interval of 6 or 8 weeks because either can be negative at any given time. The VDRL test might be a false positive Levels can vary from time to time as part of the normal workings of the immune system. I think there's also a small possibility of seronegative APS.
There is another test called anti-Beta2 glycoprotein that can help indicate whether the antiphospholipid antibodies are due to autoimmune disease or to infectious diseases such as syphilis or Lyme.
The presence of these antibodies counts towards a diagnosis of lupus - see the ACR Criteria listed in a sticky at the top of Not Yet diagnosed section. Technically speaking APS is not diagnosed until there have been clotting episodes or recurrent miscarriages according to the classification criteria for research and trials, but it can have so many other symptoms including demyelination problems very like MS, even transverse myelitis, that it might be treated with anticoagulants.

Clare
The two main tests for APS are the lupus anticoagulant, so called, which is various clotting tests, and more importantly for anti cardiolipins. They both need to be repeated at an interval of 6 or 8 weeks because either can be negative at any given time. The VDRL test might be a false positive Levels can vary from time to time as part of the normal workings of the immune system. I think there's also a small possibility of seronegative APS.
There is another test called anti-Beta2 glycoprotein that can help indicate whether the antiphospholipid antibodies are due to autoimmune disease or to infectious diseases such as syphilis or Lyme.
The presence of these antibodies counts towards a diagnosis of lupus - see the ACR Criteria listed in a sticky at the top of Not Yet diagnosed section. Technically speaking APS is not diagnosed until there have been clotting episodes or recurrent miscarriages according to the classification criteria for research and trials, but it can have so many other symptoms including demyelination problems very like MS, even transverse myelitis, that it might be treated with anticoagulants.
Clare