BACKGROUND AND OBJECTIVES: A patient experienced a severe haemolytic transfusion 
reaction. Neither the haemolytic property nor the specificity of the causative 
antibody had been sufficiently recognised when performing a microcolumn gel 
test.
MATERIALS AND METHODS: Subsequent to the transfusion reaction, the serological 
property and specificity of the causative antibody were analysed. Tube and gel 
test methods were compared, as were various reagent red cell specimens and their 
constituents.
RESULTS: A haemolytic anti-Vel was detected in the tube test. In contrast, the 
particular commercial gel test kit used did not reveal the haemolytic property 
or specificity of the antibody. Our experiments suggest that this was apparently 
due to the presence of EDTA in the low ionic strength saline solution of the 
test kit.
CONCLUSIONS: In rare cases life-treatening haemolytic activity of an irregular 
blood group antibody may be undetected by a commericial microcolum gel test kit 
in which EDTA is a constituent.