Abstract Background Hemolysis, icterus, and lipemia (HIL) are common sources of interference, potentially introducing bias and affecting the accuracy of patient results. Studies performed by manufacturers to establish HIL thresholds for interference vary across platforms and data is often limited. This study evaluates the relationship between interferent concentrations and HIL indices, and the impact of HIL interference on chemistry analytes measured on Ortho Vitros and Roche Cobas. Methods CLSI EP07-ED:2018 guidelines on evaluation of HIL interference were followed. Pooled patient plasma (N=3 per analyte) was spiked with saline (control) or increasing concentrations of hemolysate, bilirubin, or intralipid and analyzed in triplicate for 18 chemistry analytes on Ortho Vitros XT3400 (Vitros) and Roche Cobas Pro c503 (Roche) analyzers. A subset of analytes were evaluated across a broad concentration range while others were selected within the reference interval. Differences between spiked and control samples were calculated to determine interference bias. Results were compared to locally established allowable total errors (ATE) and compared to manufacturer-provided interference thresholds. Results Instrument and analyte specific differences for HIL were identified. ALP was more resistant to hemolysis on Roche than on Vitros. On Vitros, ALP bias was concentration-dependent, with increasing sensitivity to interference from hemoglobin at low ALP concentration. Total bilirubin and albumin were sensitive to hemolysis interference on Vitros, but resistant to hemolysis on Roche. Conversely, sodium was more resistant to hemolysis on Vitros but showed interference on Roche. For lipemia, Vitros showed greater resistance to interference for ALT, AST, chloride, and sodium compared to Roche. For icterus, Vitros demonstrated resistance to interference for all analytes assayed, where Roche showed concentration-dependent interference for creatinine, with increased sensitivity at lower concentrations of creatinine. Conclusion Our study showed differences in HIL interference between Roche and Vitros, with Vitros showing greater resistance, particularly to lipemia and icterus. Interference varied in a concentration-dependent manner, supporting the use of concentration-specific thresholds, especially for ALT, ALP, and AST. For many analytes on both analyzers, interference thresholds deviated from manufacturer recommendations, with higher-than-expected hemolysis thresholds and lower lipemia thresholds. These findings highlight the need for laboratories to verify HIL interference and establish optimal, analyzer-specific thresholds.
Elian et al. (Wed,) studied this question.
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