Clinical and laboratory features were evaluated in 48 patients with lupus anticoagulants and the efficiency of three different assays in the detection of lupus anticoagulants was compared. The diagnosis of lupus anticoagulants was based on a prolonged activated partial thromboplastin test not corrected in a mixture of 1:1 with normal plasma and lack of specific inhibitors against coagulation factors. Platelet neutralization procedure was positive for lupus anticoagulants in 98% of the patients, tissue thromboplastin inhibition ratio in 79%, and kaolin clotting time index in 77%. At least one of the assays was positive in 100% of the cases. The largest minority of the patients (31%) suffered from systemic lupus erythematosus. The others had a variety of non-immunological disorders. In the 13 patients who had been operated on, only 1 with renal failure developed hemorrhagic complications after renal biopsy due to thrombocytopathy. The incidence of recurrent spontaneous miscarriage, immune thrombocytopenia and positive direct antiglobulin test, anti-nuclear and anti-DNA antibodies and VDRL was significantly higher in patients with lupus anticoagulants and systemic lupus erythematosus compared to patients with lupus anticoagulants but without systemic lupus erythematosus.
