[Evaluation of the commercial ELISA method for lipoprotein(a) determination and interference by plasminogen]

We evaluated the "Tint Eliza (Bio pool, Co., Sweden)", based on an ELISA, for the determination of serum lipoprotein(a) [Lp(a)], and the immunological interference by plasminogen on the assay. Results obtained by the present assay were compared with those by our polyclonal ELISA method. The standard curve for this assay was linear to 60 mg/dl of Lp(a). Correlation with results by our method (x) was excellent: y = 0.94x + 1.2 mg/dl (n = 46, r = 0.986, Syx = 2.3). Within-run CVs for the method were 7.3, 4.8 and 4.5% at mean Lp(a) concentration of 4.0, 11.4 and 38.6 mg/dl, respectively. Detection limits were 0.6 mg/dl for Lp(a) in 1:15, 606 diluted sample. Immunological cross-reactivity of anti-Lp(a) antibody used in the present assay was observed in the immunoblot with plasminogen. In recommended procedure the specificity of Lp(a) sufficed to distinguish the cross-reactivity of plasminogen. Mean and median values of 148 blood donors were 15.5 and 11.5 mg/dl, respectively, and were compared well with those by our method.