Icteria interference for 34 clinical chemistry analytes on different analytical platforms: Method or analyzer dependent?

Objectives: In this study, we aimed to investigate the effect of increasing bilirubin concentration on 34 commonly measured clinical chemistry analytes on four different analytical platforms. We hypothesized that differences in icteria interference are not only method dependent, but also analyzer dependent.

Methods: Serum pool was prepared using leftover samples after routine laboratory blood testing. Serum pool was then spiked with dissolved bilirubin stock. Measurements were performed on all four locations at the same time. All measurements were done in duplicate. Mean value was calculated as: (value + value)/2. Those values were multiplied by corresponding dilution factors obtained during the preparation of icteric samples. For each icteric sample (I), bias against native (I) sample was calculated as ((value I- valueI)/ valueI) × 100 %. Bias was calculated with actual average values. Obtained bias values were compared against acceptance criteria according to External quality assurance (EQA) providers. Difference in bilirubin concentration across platforms was tested using Friedman ANOVA. P values < 0.05 were considered statistically significant. Data are collected and analyzed in MS Excel 2016 (Microsoft, Redmond, Washington) and MedCalc® Statistical Software version 20.015 (MedCalc Software Ltd, Ostend, Belgium).

Results: Many of the tested parameters demonstrated low sensitivity to icterus interference. The highest sensitivity to icterus was observed for triglycerides, cholesterol, and urate.

Conclusions: Our results indicate that while some common icteric interferences were consistent across all tested platforms, others were specific to the analyzer used, even when employing the same analytical methods.