Survey on lipoprotein(a) testing in Europe. A report by the EFLM Committee on Vascular Risk Biomarkers

OBJECTIVES: Lipoprotein(a) [Lp(a)] is a lipoprotein particle similar to low-density lipoprotein with an additional apolipoprotein(a) [apo(a)] covalently linked to apoB-100. Apo(a) is highly polymorphic due to a conserved sequence motif which is repeated 10 to >50-times which is a challenge to immunoassays. Harmonization of diagnostic assays is so far unsatisfactory. This includes the units to report measurement results. This survey should provide information on the current practice of Lp(a) measurement and reporting in EFLM member countries. METHODS: A questionnaire entitled "Lipoprotein (a) - Biomarkers of Cardiovascular Risk" was developed. It consisted of 38 questions for laboratories which measure Lp(a) and 21 questions for laboratories which do not measure Lp(a). A call for the survey was sent out by the EFLM to all members in December 2024. The survey remained open until end of January 2025. RESULTS: There were 340 laboratories from 40 EFLM countries completing the survey of which 247 measured Lp(a) and 93 did not. There was significant heterogeneity in assay usage, reflected by the fact that the five most common assays made up for only 53 % of all laboratories. Approx. one half each of laboratories reported Lp(a) in mass units or in molar units which was largely dependent on the manufacturer's application. CONCLUSIONS: The survey findings demonstrate that variability in Lp(a) measurement spans all phases of the testing process and involves multiple stakeholders. Laboratories can optimize pre-analytical handling and result reporting. However, the analytical domain is the most critical part which requires coordinated action between standardization bodies and IVD-manufacturers, supported by aligned clinical guidelines.