Analytical comparison between two hematological analyzer systems: CAL-8000 vs. XN-9000

This study was aimed to compare the analytical performance of traditional and new parameters and morphological flags of CAL-8000 and XN-9000. The automated differential leukocyte count (DIFF profile) and morphological flags were compared with optical microscopy (OM).

A total of 1025 peripheral blood samples, collected in K₃ EDTA tubes, were analyzed by CAL-8000, by XN-9000, and by OM. Within-run imprecision was performed in low cellularity samples. The comparison was made using Spearman's correlation, Passing-Bablok regression, Bland-Altman bias, and Cohen's K test.

Within-run imprecision in low cellularity samples yielded reproducible data between the instruments (imprecision was higher than 10% on samples with platelet count <21 × 10⁹ /L using impedance technology). Passing-Bablok regression (CAL-8000 vs. XN-9000) yielded slopes ranging between 0.2 to 1.16 and intercepts from -6.54 to 21.63. The bias for leukocytes parameters ranged from -1.8% to -82.2%, the red blood cell parameters from -2.9% to 3.1%, platelets parameters from -27.8% to 26%, and reticulocyte parameters from -115.3% to 4.5%. The comparison of morphological flags yielded a K value always <0.55. The DIFF profile vs. OM had a Passing-Bablok regression with slopes ranging between 0.34 to 1.00 and intercepts from -0.01% to 0.11 and bias ranging from -42.9% to 2.6% for XN-9000 parameters and from -2.7% to 35.0% for CAL-8000 parameters. The comparison of morphological flags showed a K value ranging from 0.35 to 0.77 for XN-9000 and from 0.17 to 0.54 for CAL-8000.

Differences exist between the two analyzers, especially in the generation of morphology flags, thus emphasizing the need of pursuing a major degree of harmonization and/or adopting instrument-specific reference ranges.