Interference Assessment for High-Performance Liquid Chromatography HbA1c Assays

Interference is a significant source of laboratory errors that can cause erroneous measurement results. In clinical practice, all the measured results should exclude the influence of interference. In this study, the ion exchange high-performance liquid chromatography of hemoglobin A1c (HbA1c) was evaluated via three brands of HbA1c analyzers, and 12 endogenous and 24 exogenous substances were added to hemoglobin solutions with different HbA1c levels to simulate the corresponding clinical samples. After the potential interfering substances were screened via interference screening testing, the interference concentration thresholds of each potential interfering substance were determined on the basis of dose–response experiment. When these substances exceed the interference concentration thresholds, elevated HbA1c values are caused by endogenous cholic acid and low pH, whereas exogenous ethanol increases HbA1c measurements in samples with low values. However, HbA1c measurements decreased in samples with high values. Although there are some differences in the thresholds of interferent concentrations between different brands of analyzers, the differences are not significant. On the basis of the detailed interference concentration thresholds and interference substances, this evidence can be provided to clinical laboratory experts and help them interpret and determine the testing results of clinical laboratories.