Peripheral blood lymphocyte immunophenotyping (TBNK) - a comparison of BD FACSCanto II and BD FACSLyric flow cytometry analysers.

Introduction: Flow cytometry immunophenotyping is a common laboratory technique for evaluating lymphocyte subpopulations. Its result remains an important diagnostic tool in various medical fields. Cytometric tests are performed in many laboratories, making the comparability between different devices using the same method an important aspect. We aimed to compare the results of lymphocyte immunophenotyping (lymphocytes B, T, Th and Tc, NK cells) between two different flow cytometers.

Material and methods: The study included 93 patients of the Children's Teaching Hospital of the Medical University of Warsaw and 9 Multi-Check control results. The method of lymphocyte subpopulation assessment was based on fluorescent flow cytometry immunophenotyping, using a BD Multitest 6-color TBNK kit (Becton Dickinson). We compared BD FACSCanto II and BD FACSLyric analysers (Becton Dickinson). For data analysis, we used Spearman's rank correlation, Bland-Altman plot and Passing-Bablok regression.

Results: Spearman's rank correlation showed a strong interrelation for all analysed parameters (0.808-0.985). In the Passing-Bablok regression analysis, all examined parameters showed linear dependence with the slope values close to 1 (0.940-1.134). Bland-Altman coefficient values were within the range of 2.94-8.62% with half of them being above 5% (T, Tc, Th, B, NKT absolute values and B percentage values).

Conclusions: The results from both cytometers can be considered equivalent, but it should be noted that one of the statistical methods showed some deviations, presumably primarily due to the evaluators' different gating techniques. The training of specialists performing these tests requires more attention.