Abstract / Summary
Background & aim: Lipoprotein(a) (Lp(a)) is an established predictor of cardiovascular risk. Recent evidence suggests that Lp(a) testing with subsequent intervention could be economically advantageous, and several organizations now recommend population testing. However, general population datasets are scarce, and healthcare services already under pressure may not be able to undertake large-scale testing programs using traditional sampling methods, even when financially beneficial. However, self-collected capillary blood samples offer several advantages over venous collections, primarily by enabling patients to collect samples whenever and wherever they choose, removing the phlebotomist bottleneck. This patient-centric approach has become increasingly popular because of its convenience. Evidence regarding the comparability of venous and capillary samples for various routine analytes remains limited. Moreover, questions remain about the stability of these analytes in whole-blood samples over time, particularly when separation is delayed before analysis. This project aimed first to review a UK-wide Lp(a) dataset and compare it with other recently published UK Biobank data, and second to determine whether screening could be performed using capillary blood. This was done by investigating venous and capillary comparability and sample stability in various anticoagulants over 72 hours. Materials & methods: Serum Lp(a) concentrations from 5298 venous samples collected between January 2025 and June 2025 were provided from a UK-wide population dataset and compared with a recently published UK Biobank dataset. Stability studies were organized as follows. Five paired venous and capillary serum samples were collected and tested on day zero to serve as an initial baseline verification. We collected a further 22 paired capillary and venous blood samples. The venous sample was tested on day zero, and the capillary sample was stored as whole blood at room temperature and processed 72 h later. A further 10 samples were obtained to confirm day-zero and 72 h comparability between venous serum and EDTA plasma samples. Results were compared using Pearson’s correlation, Bland–Altman and Passing–Bablok analyses. Results: Statistical analysis showed that Lipoprotein (a) levels in capillary and venous serum and plasma samples were comparable, and that the analyte was stable in unspun blood across all the matrices tested for at least 72 h before analysis. Conclusion: We believe this is the first published study to determine the comparability and stability of venous and capillary measurements of Lp(a). This study indicates that Lp(a) analysis is feasible using self-collected capillary samples returned to the laboratory via the postal system.