Comparative assessment of dithiothreitol-treated ABO isoagglutinin titres performed by two methods

Background and aims

To determine actual concentration of clinically significant IgG antibodies, there is need to inactivate IgM antibodies. Aim of this study was to study effect of dithiothreitol (DTT) on ABO isoagglutinin titres performed by column agglutination technology (CAT) and conventional tube technique (CTT) and to compare results obtained by DTT treatment.

Materials and methods

This was a prospective, observational study conducted from October 2019 to March 2020. All consecutive A, B and O group donors were included. All samples were consecutively tested by CTT and CAT, before and after DTT treatment (pCTT, pCAT).

Results

A total of 300 donors were included, 100 each from group A, B and O. IgG titres were found to be more than IgM titres. For group O, IgG titre results were higher for both anti-A and anti-B compared with group A and B. Reduction in IgG titres was observed with DTT. With the use of DTT, one log reduction in group O IgG titres was observed and three log reduction in group A/B IgG titres was observed. When comparing anti-A and anti-B IgG results for group O individuals, results of CTT and pCAT were not found to be significant. IgG measurement of anti-A and anti-B of group O individuals showed strong to very strong correlation between CTT and CAT, before and after DTT treatment.

Conclusion

There is significant difference between antibody titres estimated using DTT-treated and DTT-untreated plasma. Use of DTT for ABO isoagglutinin titre estimation is recommended.