Analytical Agreement and Diagnostic Performance of a Commercial Point-of-Care Lipid Testing System for Lipid Profile and Atherogenic Ratios

Background: Point-of-care testing (POCT) devices offer a rapid alternative for lipid assessment, but comprehensive analytical validation against reference laboratory methods remains limited. Objective: This study aimed to evaluate the agreement, systematic bias, and diagnostic performance of the Mission® Cholesterol 3-in-1 system for lipid profile measurements and atherogenic ratios. Methods: A prospective cross-sectional agreement study was conducted among 120 participants. Lipid profiles were measured using eleven Mission® Cholesterol 3-in-1 analyzers and compared with those measured using the reference laboratory method. Agreement was assessed using the intraclass correlation coefficient (ICC), concordance correlation coefficient (CCC), coefficient of determination (R2), root mean square error (RMSE), mean absolute error (MAE), percentage bias, Bland–Altman plots, Passing–Bablok regression, and diagnostic accuracy. Results: Triglycerides demonstrated excellent agreement (ICC = CCC = 0.972; bias = 5.19%), whereas total cholesterol, HDL-C, non-HDL-C, and LDL-C showed good agreement (ICC range: 0.817–0.854). Among the atherogenic ratios, TG/HDL-C (ICC = 0.932) and TG/LDL-C (ICC = 0.931) exhibited the highest concordance. Passing–Bablok regression revealed constant bias for all analytes, except for LDL-C estimated using the Sampson equation and the TG/LDL-C ratio, while proportional bias was observed for all analytes, except for triglycerides and the TG/LDL-C ratio. Despite these systematic differences, diagnostic performance remained excellent, with sensitivities of 94.29–98.33% and specificities of 68.33–91.80%. Conclusion: The Mission® Cholesterol 3-in-1 system shows good analytical agreement with laboratory testing, particularly for triglycerides and the HDL-C, TG/HDL-C, and TG/LDL-C ratios. Although systematic bias limits complete interchangeability with reference methods, its excellent diagnostic performance supports its use as a rapid point-of-care screening tool, especially in resource-limited settings.