University Medical Center New Orleans, Louisiana, United States
Background/Case Studies: Immunohematology, though crucial, remains an imperfect science, emphasizing the significance of comprehending the methods and technologies employed in decision-making regarding testing algorithms. While existing guidelines underscore consistency in antibody detection and identification methods, there is lack of guidance extending this principle to crossmatching. Multiple sources indicate that nonspecific reactivity in highly sensitive methods may precede the emergence of clinically significant antibodies during subsequent workups. Our laboratory offers various testing methodologies, including Solid Phase (SP) and hemagglutination (tube) technique utilizing polyethylene glycol (PeG) as enhancement media. This retrospective study aims to address the optimal method for AHG crossmatches in our laboratory, with broader implications for transfusion medicine practices.
Study
Design/Methods: A retrospective analysis of antibody identification workups conducted in 2023 was undertaken. Patients exhibiting nonspecific reactivity were identified, and the method of crossmatching—either tube or SP—was assessed for its potential impact on patient care.
Results/Findings: Among the 320 antibody workups reviewed, 19 patients presented with nonspecific reactivity on solid phase with or without additional antibody specificities.117 Crossmatches were performed across these 19 patients by solid phase.38 of those crossmatches (32%) were incompatible.All units were antigen-negative for any known corresponding antibody specificities. Notably, 21% of these patients revealed a newly detected significant antibody in subsequent workups. (Table 1) Conclusions: Nonspecific reactivity, whether indicative of declining antibody titers or the emergence of new antibodies, underscores the complexity of immunohematology testing. Our study reinforces the importance of conducting AHG-phase crossmatches using the same methodology employed for antibody detection. This approach ensures a higher level of patient care by mitigating the risk of potential transfusion reactions through the identification and avoidance of incompatible crossmatches. Disregarding nonspecific reactions as inconsequential without conducting crossmatching using the detecting methodology poses a significant risk to patient safety. As well established in other studies, this nonspecific reactivity may be absent in less sensitive methods. Our findings reaffirm the practice of performing crossmatches in solid phase, aligning with the method of detection and identification in optimizing patient care.In 32% of the units crossmatched when nonspecific reactivity was present, patient safety was potentially improved by avoiding transfusion of these units.
