A-116 Evaluation of Lp(a) Ultra assay for the Immunoturbidimetric Quantitative Determination of Lipoprotein (a) in Human Serum and Plasma With Siemens Healthineers Atellica CH 930 Analyzer

Abstract Objective The aim of this study is to evaluate the analytical performances of the Lp(a) Ultra assay for the immunoturbidimetric quantitative determination of lipoprotein (a) in human serum and plasma on Siemens Healthineers Atellica CH 930 Analyzer. Background Lipoprotein (a) has been found in artery walls and can have atherogenic effects. Because of its structural similarity to plasminogen, it can also inhibit fibrinolysis and hence acts thrombogenically. High Lp(a) concentrations in serum correlate with premature manifestation of atherosclerosis and strokes. In combination with elevated LDL Cholesterol concentrations, the coronary risk increases approximately six-fold. Methods Lp(a) Ultra is a latex immunoassay manufactured by Sentinel Diagnostics and developed to measure Lp(a) levels. If the antigen-antibody reaction takes place between Lp(a) in the sample and the anti-Lp(a) antibodies, which have been adsorbed to latex particles, agglutination occurs. This agglutination is detected as an absorbance change, with the magnitude of the change being proportional to the quantity of Lp(a) contained in the sample. Results The Limit of Blank LOB (4 samples × 5 replicates × 3 runs) was ≤2.0 mg/dL. The Limit of Detection LOD (4 samples × 5 replicates × 3 runs) was ≤ 3.0 mg/dL. The Limit of Quantitation LOQ (8 dilution levels × 10 replicates × 3 runs) was ≤5.0 mg/dL at %CV lower than 20%. The Intra Assay (5 samples × 20 replicates × 3 runs) gave the following %CVs: 2.4% at 12.1 mg/dL, 0.8% at 30.3 mg/dL, 0.6% at 47.8 mg/dL, 0.5% at 58.8 mg/dL, 1.7% at 87.1 mg/dL. Total precision study (5 samples × 2 runs × 2 replicates × 20 runs) gave the following %CVs: 4.0% at 11.5 mg/dL, 3.6% at 21.7 mg/dL, 3.0% at 32.0 mg/dL, 2.8% at 42.2 mg/dL, 2.3% at 50.7 mg/dL. The test was linear up to 130 mg/dL. Calibration stability was up to 30 days. Reagent on board stability was up to 30 days. This application (y) was compared with the same test applied on Beckman Coulter AU680 Analyzer (x) and gave the following results: using Passing Bablok analysis: y = 0.8 + 1.0x; correlation coefficient (r) = 0.997; using Deming analysis: y = 1.0 + 1.0x; correlation coefficient (r) = 0.997; number of samples = 120. There is not Hook effect/antigen excess up to 600 mg/dL. Conclusions Analytical performances of Lp(a) Ultra assay on Siemens Healthineers Atellica CH 930 Analyzer meet the requirements for its use as immunoturbidimetric quantitative determination of lipoprotein (a) in human s