Which condition is most likely to cause interlaboratory variation in bilirubin results?

The condition most likely to cause interlaboratory variation in bilirubin results is the use of different bilirubin calibrators. Calibration is critical in ensuring accurate and consistent measurements across different laboratory settings. Each laboratory may use different standards or calibrators, which can lead to variations in how bilirubin concentrations are reported.

When laboratories employ distinct calibrators, there might be differences in how these calibrators are defined or standardized, leading to inconsistent results. This variation can affect not only the absolute values obtained but also the reference ranges that the labs use, potentially causing confusion in clinical interpretation.

While laboratory errors in specimen handling, variations in reagent precision, and inconsistent testing frequency can introduce errors within a single laboratory, they do not typically result in the widespread interlaboratory differences seen with calibrator variation. Calibration discrepancies are a more systematic source of variation that can occur across different facilities and impact the comparability of results more significantly.