The cutoff values for positive aCL was calculated to be at least the 95th percentile of healthy blood donors. Autoantibodies to b2-glycoprotein1 (ab2GP1, IgG) were analyzed by ELISA (Orgentec Diagnostika, Mainz, Germany). Positive cutoff levels were used according to the manufacturers’ descriptions. Borderline results were regarded as negative. Lupus anticoagulant (LAC) was determined using a modified dilute Russell viper venom method, (Biopool, Umea, Sweden) using Bioclot LAC.