Comparison of Two Point-of-Care Lipid Analyzers for Use in Global Cardiovascular Risk Assessments

Abstract

Point-of-care (POC) lipid testing is increasingly used in community- and office-based practice. Two analyzers commonly used in the US are CardioChek PA and Cholestech LDX. Both directly measure total cholesterol (TC) and high-density lipoprotein cholesterol (HDL-C), mandatory values in calculating a Framingham Risk Score (FRS). The FRS in turn informs the clinician of the need for lipid-modifying therapy and the degree of therapeutic intensity. To compare the performance of CardioChek PA and Cholestech LDX. Staff members from the Colorado Prevention Center were included in the study, with all having fasted for 12 hours before the testing. No medical history was obtained. A venous blood sample was collected for lipid measurements conducted in a laboratory, and 2 finger sticks were obtained at that time and analyzed immediately on-site using the POC analyzers. Intraclass correlation coefficients (ICCs) were determined for each analyzer versus the laboratory analysis, with values greater than 0.75 defined as indicators of excellent reproducibility. We then assessed how interanalyzer differences in TC or HDL-C impacted the FRS lipid categorization. Thirty-four adults (aged 24-56 y) participated in the study. The ICC between Cholestech LDX and the laboratory standard exceeded 0.75 for all 4 lipid categories (TC, rho = 0.96; HDL-C, rho = 0.88; low-density lipoprotein cholesterol, rho = 0.87; triglycerides, rho = 0.99). By contrast, the only ICC exceeding 0.75 using CardioChek PA was for triglycerides (rho = 0.84). When applied in calculating the FRS, the Cholestech LDX analyzer misclassified fewer individuals for TC versus the CardioChek PA analyzer (5 vs 21). Overall, Cholestech LDX provided TC and HDL-C values in the correct FRS category more frequently versus CardioChek PA (TC, p < 0.001; HDL-C, p < 0.001). Limitations of the study include use of only 2 POC products and small sample size with no known risk factors. This project does not prove superior accuracy of either device, but reflects a real-world comparison of the analyzers conducted at a single center. The Cholestech LDX analyzer demonstrated better reproducibility than the CardioChek PA analyzer when compared with laboratory gold standard analysis and allowed more accurate categorization for FRS. Since results obtained from these analyzers have the potential to impact treatment decisions, larger, prospective, comparative studies seem warranted.