ARTICOLO ORIGINALE   

La Rivista Italiana della Medicina di Laboratorio 2023 Marzo;19(1):30-40

DOI: 10.23736/S1825-859X.23.00178-0

Copyright © 2023 EDIZIONI MINERVA MEDICA

language: Italian

Verification of leukocyte contamination in leucodepleted blood components using Blood Bank mode of Sysmex XN-1000 haematology analyzer

Angela GENICCO ¹ ✉, Chiara RYCHLICKI ², Lidia DA LIO ³, Mauro MONTANARI ², Marco MORETTI ³

¹ SOD Anatomia Patologica, Azienda Ospedaliero Universitaria delle Marche, Ancona, Italia; ² SOD Medicina Trasfusionale, Azienda Ospedaliero Universitaria delle Marche, Ancona, Italia; ³ SOD Medicina di Laboratorio, Azienda Ospedaliero Universitaria delle Marche, Ancona, Italia

BACKGROUND: Quality control of residual leukocytes in leukodepleted blood components for transfusion use is essential to ensure transfusion safety and to minimize adverse reactions. At Transfusion Medicine Department (Ancona, Italy) this verification is carried out with the semi-automatic analyzer ADAM-rWBC (ADAM). In this study, the Sysmex XN-1000 (XN-BB) Blood Bank mode was evaluated, in order to establish whether it could represent a valid alternative to the reference technique.
METHODS: The study analyzed a group of 100 samples collected from leukodepleted blood components. The samples were tested both with ADAM, an optical system able to analyze fluorescence images after propidium iodide staining, and with XN-BB, which uses the fluorescence flow cytometry method for counting residual leukocytes. The experimental variables taken into consideration were the time elapsed between the leucodepletion of the units and the day of the actual analysis and the use of tubes with/without K2EDTA. The comparability, linearity and precision profiles were also evaluated by preparing a suspension of white blood cells (WBC) at known concentration and setting up serial dilutions in replicates.
RESULTS: The rWBC/µL (residual WBC) count deltas between the two instruments increase as a function of time with a higher bias for blood components analyzed after 7 days (0.23) and a lower bias (-0.01) for blood components analyzed the day after leukodepletion. In the samples collected in K2EDTA tubes, the agreement between the two methods was 100%. 8.3% of the samples without K2EDTA showed non complaint results with higher numbers of rWBC/µL on XN-BB. Linearity and precision results showed for both instruments an excellent linear correlation between expected (0.5 to 30 rWBC/µL) and measured WBCs for the whole range of concentrations tested. The limit of quantitation (LoQ) values were also adequate for both methods (0.5 WBC/µL for ADAM; 1.4 WBC/µL for XN-BB).
CONCLUSIONS: The results demonstrate full agreement and comparability between the two methods in the evaluation of the leukodepletion procedure and confirm the literature data on the preferential use of K2EDTA test tubes in order to avoid interference phenomena. Both methods exhibit a similar linear response and accuracy profile. The LoQ values for XN-BB confirm the data declared by Sysmex and those obtained from previous studies carried out to date regarding the leukocyte contamination cut-off, demonstrating that the system under test guarantees adequate analytical performance and can therefore represent a valid alternative to the method in use, thanks also to its greater automation, speed of response, completeness of reporting, security of analysis and cost-effectiveness.

KEY WORDS: Blood banks; Quality control; Blood transfusion; Blood component transfusion