Lipoprotein(a): what's in a measure?

Abstract

Lipoprotein(a) [Lp(a)] was first identified by Kare Berg in 1963 as an LDL variant. Subsequent studies showed it to be a family of lipoproteins whose wide density range overlaps those of low and high density lipoproteins. Although clinical interest in this particle was limited for many years, it was stimulated again in the late 1970s with the discovery that high concentrations of Lp(a) may be associated with coronary heart disease (CHD). Numerous follow-up studies confirmed that Lp(a) is an independent risk factor for CHD and that raised values are associated with the severity of CHD and with an increased risk of future cardiac events. The relative risk of myocardial infarction has been reported to be 1·75-fold higher when Lp(a) levels are raised above 300 mg/L. Clinical interest in Lp(a) has stimulated the development of commercial methods for its determination. Currently, over 15 methods are available, varying in principle, antibody specificity, standardization and method of detection. This personal view considers the impact that different methodological approaches have had on the interpretation of Lp(a) levels in clinical studies and the initiatives now being taken to standardize the measurement of this heterogeneous particle.