Immunochemical quantification of free light chains in urine.

kIU/L; normal values 18 kIU/L) autoantibodies, and 2 were negative for all anti-phospholipid antibodies investigated by the ELISA method. Thus, the new SCT assay was positive in 87% of those who had a positive result by our LA test and was negative in 93% of those whose results were negative by our LA assay. All of these patients had histories of thromboembolic disease (4 with venous thrombosis and 2 with arterial thrombosis). These findings can suggest, at least in some patients, a role of SCT as an independent risk factor for thrombosis. Furthermore, the presence of SCT positivity in patients with thromboembolic events reduces, at least in part, the number of patients who are otherwise seronegative for anti-phospholipid autoantibodies. More data and prospective studies are needed to confirm this hypothesis.