Transforming ABO IgG titration: Real-world comparison of automated SPRCA vs. CAT with dithiothreitol (DTT) inactivation of IgM in 1600 ABO-incompatible solid organ transplant patient samples

Amena Ebadur Rahman; Rasika Dhawan Setia; Mitu Dogra; Abhideep Chaudhary; Ashwini Goel; Amit Kumar Singhal; Vadad; Sonia Joseph; Priyasha Prajapat

doi:10.1016/j.transci.2025.104198

Transforming ABO IgG titration: Real-world comparison of automated SPRCA vs. CAT with dithiothreitol (DTT) inactivation of IgM in 1600 ABO-incompatible solid organ transplant patient samples

Transfus Apher Sci. 2025 Jun 27;64(4):104198. doi: 10.1016/j.transci.2025.104198. Online ahead of print.

Authors

Amena Ebadur Rahman¹, Rasika Dhawan Setia², Mitu Dogra¹, Abhideep Chaudhary³, Ashwini Goel⁴, Amit Kumar Singhal³, Vadad¹, Sonia Joseph¹, Priyasha Prajapat¹

Affiliations

¹ Department of Transfusion Medicine, BLK-Max Super Speciality Hospital, New Delhi, India.
² Department of Transfusion Medicine, BLK-Max Super Speciality Hospital, New Delhi, India. Electronic address: rasika_setia@yahoo.co.in.
³ HPB Surgery & Liver Transplant, BLK-Max Super Speciality Hospital, New Delhi, India.
⁴ Nephrology & Renal Transplant, BLK-Max Super Speciality Hospital, New Delhi, India.

PMID: 40592016
DOI: 10.1016/j.transci.2025.104198

Abstract

Anti-ABO IgG isohemagglutinin(IHA) titration plays a vital role in guiding ABO-incompatible solid organ transplantation(ABOi-SOT). Column agglutination technology (CAT), though widely used, requires DTT pre-treatment to eliminate IgM interference. This poses significant challenges, including subjectivity, inconsistent IgM inactivation, frequent sample gelling, and prolonged turnaround times(TAT), all of which compromise accuracy and standardization. These limitations have prompted global interest in DTT-free, IgG-specific methods that enhance analytical precision and workflow efficiency.

Study design and methods: This prospective single-centre study (August 2019-October 2024) evaluated 1622 samples from 300 ABOi-SOT candidates; baseline titres done for all; 139 underwent transplantation. IgG titers were assessed via DTT-treated CAT [CAT(DTT)] and SPRCA during desensitization phase and post-transplant monitoring. IHA IgG titers were compared between CAT(DTT) and fully automated solid-phase red cell adherence assay (SPRCA). Concordance & reproducibility was assessed using Pearson's correlation and Cohen's kappa and TATs compared.

Results: SPRCA showed strong correlation with CAT (DTT) for IgG titers (r = 0.949; κ = 0.71), with 91.4 % of values within ±1 dilution. Mean IgG TAT was significantly lower for SPRCA (65.26 ± 14.41 min) compared to CAT (DTT) (111.43 ± 19.5 min; p < 0.0001). SPRCA demonstrated minimal inter-technologist variability and elimination of manual pre-DTT treatment steps translating to faster, more consistent results, enabling timely therapeutic decisions.

Conclusion: SPRCA is a robust, automated, and IgG-specific platform that overcomes key limitations of CAT. Its implementation in transplant workflows can enhance standardization, reduce delays, and support better outcomes, particularly critical in high-throughput ABOi transplant settings.

Keywords: ABO incompatible transplantation; Antibody titration; Column agglutination technique; Isohemagglutinins; Solid-phase red cell adherence assay.