Evaluation of immunohematologic routine methods using the new erythrocyte-magnetized technology on the QWALYS 2 system.
BACKGROUND
QWALYS 2 is a fully automated system for ABO/D grouping, Rh phenotyping, K typing, and antibody screening (ABS). Its new erythrocyte-magnetized technology (EMT) is based on the use of magnetic nanoparticles and avoids centrifugation and washing steps.


METHODS
Overall 499 blood samples were tested with our routine blood bank methods for ABO/D grouping, 313 samples for Rh phenotyping and K typing (microtiter plates; Olympus PK 7200), and 478 samples for ABS (gel centrifugation technique, DiaMed). All samples were tested in parallel with the EMT.


RESULTS
In 496 of 499 samples (99.4%), a complete concordance between the observed (QWALYS 2) and the expected results for ABO/D grouping was found. One sample with a weak A in an AB blood group and 2 samples with a weak D were not detected by the QWALYS system. Rh phenotyping and K tests revealed a 100% concordance. In the two ABS techniques, 427 samples were negative in both and 15 samples showed the same antibody specificity in both. Three immunoglobulin M antibodies were as expected negative in EMT and positive by DiaMed. In 32 cases (6.7%), false-positive reactions were observed by EMT due to 22 unspecific reactions (4.6%) and 10 lipemic or fibrinic plasmas (2.1%). One autoantibody was found by EMT only.


CONCLUSIONS
The EMT is reliably suited to ABO/D grouping, Rh phenotyping, and K testing and is suitable to detect immunoglobulin G red blood cell alloantibodies as well. The rate of false-positive reactions in ABS due to lipemic and fibrinic samples needs to be reduced.
Schoenfeld
Helge
H
Department of Anesthesiology and Intensive Care Medicine, Charité-Universitätsmedizin Berlin, Charitéplatz 1, Berlin, Germany. helge.schoenfeld@charite.de
Bulling
Katia
K
von Heymann
Christian
C
Neuner
Bruno
B
Kalus
Ulrich
U
Kiesewetter
Holger
H
Pruss
Axel
A
D000017:ABO Blood-Group System / Q000276:immunology; D001788:Blood Grouping and Crossmatching / Q000379:methods*; D006801:Humans; D007626:Kell Blood-Group System / Q000276:immunology; D012204:Rh-Hr Blood-Group System / Q000276:immunology
D000017:ABO Blood-Group System; D007626:Kell Blood-Group System; D012204:Rh-Hr Blood-Group System