The enhanced direct antiglobulin test in current practice has a limited impact on management of adult patients

Abstract

IntroductionThe direct antiglobulin test (DAT) identifies immunoglobulin IgG and/or complement onthe red blood cell surface, allowing discrimination between immune and non-immunehemolysis. When the DAT is negative but there is clinical suspicion for immunehemolysis, an enhanced DAT can be sent to an immunohematology referencelaboratory (IRL). MethodologyThis retrospective study assessed the volume of enhanced DATs at a large tertiarycare center and evaluated their impact on patient care. Enhanced DATs were sent on21 adult patients (January 2019 - January 2021) at the University of Pittsburgh MedicalCenter and Allegheny Health Network. Laboratory and clinical data were collected andanalyzed. ResultsFour out of 21 patients had positive tests (DAT and other serologic tests) at the localIRL. Enhanced DAT testing yielded positive results in an additional 5 patients butnegative or invalid results for 2 patients. High-dose steroid therapy was started in 12patients prior to receipt of enhanced DAT results. Enhanced DAT testing was sent amedian of 5 days after initiation of steroid therapy. For the patients trialed on steroids,the enhanced DAT results impacted medical decision-making in only 3 patients, and inonly one of those patients was the enhanced DAT positive despite a negative DAT at alocal IRL. In the non-steroid treated patients, enhanced DAT results did not contributeto clinical decision-making. ConclusionEnhanced DATs generally did not impact medical decision-making in adults withhemolytic anemia.