Comparative evaluation of the microcolumn gel card test and the conventional tube test for measurement of titres of immunoglobulin G antibodies to blood group A and blood group B.

The conventional tube test (CTT) and microcolumn gel card test (MG) were used to measure immunoglobulin G (IgG) antibody titres to blood group A (anti-A) and blood group B (anti-B) in 288 serum samples. Diagnostic concordance and correlations between the two methods were analysed. MG was more sensitive than CTT in the detection of both anti-A and anti-B IgG. Correlation coefficients for the two methods for the titration of anti-A and anti-B were 0.8470 and 0.8336, respectively. The regression equation representing the relationship between the two methods was calculated and used to convert critical values for anti-A and anti-B IgG antibodies determined by CTT to critical values for MG titration. Analyses showed 86.8% and 89.9% diagnostic concordant rates for the detection of anti-A and anti-B IgG, respectively. It was concluded that titration results obtained by MG correlate well with those obtained by CTT, but critical values determined by CTT need to be converted into corresponding MG values.