Lupus anticoagulant in Thai systemic lupus erythematosus patients.

: In the past decade, interest in the potential clinical significance of lupus anticoagulant (LA) has grown tremendously. Recent reviews from the Western countries have found an average frequency of 34% for LA in patients with systemic lupus erythematosus (SLE). By using various laboratory procedures, namely, standard and diluted activated partial thromboplastin time, kaolin clotting time, tissue thromboplastin inhibition test and platelet neutralization test, we found the frequency of LA in 91 consecutive Thai SLE patients to be 17.5%, compared with 0.8% in the age-matched normal control population. The presence of LA was significantly associated with disease activity (p = 0.01). A statistically significant association was also observed between the presence of LA and convulsive disorders (p = 0.04), thrombocytopenia (p = 0.001) and autoimmune hemolytic anemia (p = 0.02).