The laboratory diagnosis of the antiphospholipid syndromes involves testing for both lupus anticoagulants and anticardiolipin antibodies in patients with clinical findings such as unexplained thrombosis or fetal wastage.
Testing |
Interpretation |
prolonged dRVVT, shortened by addition of cephalin |
lupus anticoagulant |
prolonged dRVVT, not shortened by addition of cephalin |
coagulation factor defect |
ELISA testing positive for IgG, IgA and IgM anticardiolipin antibodies with elevated titers, reported in PL (phospholipid) units |
anticardiolipin antibodies, increased |
ELISA testing positive for IgG, IgA and IgM anticardiolipin antibodies but levels within the normal range or minimally increased |
anticardiolipin antibodies present, not significant |
ELISA testing negative for IgG, IgA and IgM anticardiolipin antibodies |
no anticardiolipin antibodies |
where:
• dRVVT is the dilute Russell's viper venom test
• Testing for correction of dRVVT by addition of cephalin is termed cephalin neutralization.
Interpretation:
• If either lupus anticoagulants or increased anticardiolipin antibodies levels are present, then the antiphospholipid syndrome should be considered.
• The diagnosis of antiphospholipid antibody should not be made on a single abnormal test. It is important to demonstrate that the antibody is persistent in a patient with appropriate clinical findings, with at least 2 positive values at least 6 weeks apart.
Specialty: Hematology Oncology, Clinical Laboratory, Immunology/Rheumatology