Summary
Lipoprotein(a) is considered an independent risk factor for atherosclerosis. A variety of analytical methods have been proposed for lipoprotein(a) measurement, the majority of which require dedicated instruments and are costly to perform, particularly when the aim is to screen for high lipoprotein(a) concentrations in large populations. We evaluated the sensitivity and specificity of a newly developed semi-quantitative latex method to assess its suitability for identifying subjects with high lipoprotein(a) levels. Based on clinical data, a sensitivity limit of 20 mg/dl of total lipoprotein(a) particle was selected for the latex method. Results obtained by the latex method on 204 subjects were compared with two enzyme immunoassays using two anti-apo(a) monoclonal antibodies with different specificities. In one assay, the detecting monoclonal antibody (MAb a-5) is directed against an epitope present in a variable number depending on the apo(a) size isoforms in lipoprotein(a), while the other assay the detecting monoclonal antibody (MAb a-40) is directed against an epitope present only once in lipoprotein(a) particles, irrespective of their apo(a) size. Both the latex method and the MAb a-5 assay demonstrated a 100% sensitivity, in that no false-negative results were found using the MAb a-40 assay as the gold standard. Eleven subjects (5.4%) were misclassified as false positive by MAb a-5 assay and 23 (11.3%) were misclassified by the latex method. Based on its 100% sensitivity and 89% specificity, we conclude that the lipoprotein(a) latex method is a cost-effective rapid approach for screening large populations.
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Marcovina SM, Morrisett JD. Structure and metabolism of lipoprotein(a). Curr Opin Lipidol 1995; 6: 136.
McLean JW, Tomlinson JE, Kuang W-J, Eaton DL, Chen EY, Fless GM, Scanu AM, Lawn RM. cDNA sequence of human apolipoprotein(a) is homologous to plasminogen. Nature 1987; 330: 132.
Morrisett JD, Gaubatz JW, Knapp RD, Guevara JG Jr. Structural properties of apo(a): a major apoprotein of human lipoprotein(a). In: Scanu A, ed. Lipoprotein(a). San Diego: Academic Press; 1990: 53–74.
Lackner C, Cohen JC, Hobbs HH. Molecular definition of the extreme size polymorphism in apolipoprotein(a). Hum Mol Genet 1993; 2: 933.
Marcovina SM, Zhang Z-H, Gaur VP, Albers JJ. Identification of 34 apolipoprotein(a) isoforms: differential expression of apolipoprotein(a) alleles between American Blacks and Whites. Biochem Biophys Res Commun 1993; 191: 1192.
Marcovina SM, Levine DM, Lippi G. Lipoprotein(a): structure, measurement, and clinical significance. In: Rifai N, Warnick R, eds. Laboratory measurement of lipids, lipoproteins, and apolipoproteins. Washington DC: AACC Press; 1994: 235–263.
Marcovina SM, Albers JJ, Gabel B, Koschinsky M, Gaur VP. Effect of the number of apolipoprotein(a) kringle 4 domains on immunochemical measurements of lipoprotein(a). Clin Chem 1995; 41: 246.
Lippi G, Ruzzenente O, Facchinetti R, Guidi GC. Semi-quantitative latex method for lipoprotein(a) assay. Clin Chim Acta 1994; 229: 147.
Marcovina SM, Albers JJ, Jacobs Jr DR, Perkins LL, Lewis CE, Howard BV, Savage P. Lipoprotein(a) concentrations and apolipoprotein(a) phenotypes in Caucasians and African Americans. The CARDIA Study. Arterioscler Thromb 1993; 13: 1037.
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Marcovina, S.M., Lippi, G. & Guidi, G. Lipoprotein(a) immunoassays: comparison of a semi-quantitative latex method and two monoclonal enzyme immunoassays. Int J Clin Lab Res 25, 201–204 (1995). https://doi.org/10.1007/BF02592698
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DOI: https://doi.org/10.1007/BF02592698