Development of a fully automated latex-enhanced immunoturbidimetric method for quantitative serum Lp(a) measurement.

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Lipoprotein (a) [Lp(a)] is a critical factor in cardiovascular health, composed of low-density lipoprotein-like particles bound to apolipoprotein (a). Elevated Lp(a) levels are associated with an increased risk of cardiovascular diseases (CVD), accelerating disease progression and raising CVD-related mortality. However, the lack of standardized measurement methods for Lp(a) contributes to diagnostic uncertainties in this area. A quantitative measurement method for serum Lp(a) was developed using fully automated latex-enhanced particle immunoturbidimetry, marking a significant advancement in diagnostic capabilities. Key parameters, including repeatability, stability, linearity, detection limit, interference, and method comparison, were evaluated to ensure the assay's reliability and accuracy. Lp(a) in samples was detected by carboxylated latex particles (95nm in diameter) covalently coated with anti-Lp(a) antibodies. Lp(a) concentration was quantified by measuring the turbidity changes caused by agglutination at 600nm. This method provides rapid, accurate, and fully automated measurements on the Hitachi 7100 automatic biochemical analyzer. With intra-batch precision CV% of 1.10% and inter-batch precision CV% of 1.79%, the method demonstrates reliable performance with Randox biochemical quality control samples. It has a detection limit of 7mg/L and a high correlation coefficient (R2 = 0.9946) within the 0-1500mg/L range. Minimal interference from bilirubin, fat emulsion, hemoglobin, and ascorbic acid was observed. Additionally, it shows strong correlation (R2 = 0.9972) with a commercially available latex-enhanced immunoturbidimetric Lp(a) assay reagent, confirming its comparability and clinical suitability. The quantitative serum Lp(a) determination method based on latex-enhanced immunoturbidimetry offers numerous advantages. It provides rapid, accurate, and automated results, making it ideal for routine clinical testing. The method effectively measures Lp(a) in serum samples by leveraging the interaction between Lp(a) and latex particles.