Precision and bias evaluation of three different triglyceride assays: Discrepant bias per the CLSI EP15-A3 and EP09-A3 guidelines
Abstract
Background
Besides its clinical importance, triglyceride (TG) measurement plays a critical role in calculating Low-Density Lipo-protein Cholesterol (LDL-C). Therefore, it is important to highlight any biases when changing methods. The Clinical Laboratory Standards Institute (CLSI) EP09-A3 recommends evaluating bias between two methods using fresh samples, while EP15-A3 suggests verifying precision and estimating bias, with quality control (QC) material as an option for samples.
Methods
The performance of three different TG reagents (Abbott Triglyceride, Abbott Triglyceride-2, and Archem Triglyceride) with EP09-A3 and EP15-A3 and the effects of TG results on LDL-C calculations were evaluated.
Results
Notable inconsistencies were observed between biases from patient samples and QC materials. The lowest QC measurements and the highest patient results were both seen with Abbott TG. While median bias values were within acceptable limits, there were discrepancies in slope and intercept values between TG reagents. The bias in LDL-C values calculated using Friedewald’s and Sampson’s equation was acceptable, but the Martin-Hopkins equation showed even less bias. The Abbott TG reagent fully met the imprecision criteria, the Abbott TG 2 reagent partially but clinically acceptably met them, whereas the Archem TG reagent, despite having imprecision values below the optimum CV, failed to meet the manufacturer’s claims.
Conclusions
This discrepancy in bias between patient samples and QC materials underscores the challenge of control material commutability. Laboratories should assess bias when switching methods using the practical EP09-A3 approach, and perform an EP15-A3 verification study before introducing any new kit into routine use.
© 2026 Hatice Bozkurt Yavuz, Soycan Tüner, published by Romanian Association of Laboratory Medicine
This work is licensed under the Creative Commons Attribution 4.0 License.