A new study has determined that using enhanced direct antiglobulin tests (DATs) to diagnose autoimmune hemolytic anemia (AIHA), of which cold agglutinin disease (CAD) is a form, does not appear to have a significant impact on decision making with these patients.  

The study, published in Transfusions and Apheresis Science, noted that pathologists can provide important consultation to the clinical team regarding appropriate in-house testing to guide the diagnostic process.

“If there is strong clinical suspicion for AIHA but the DAT is negative, experts recommend repeating the DAT, preferably at an immunohematology reference laboratory,” the authors wrote. “The study was designed and performed to understand clinician practice patterns in evaluating hemolytic anemias in adult patients and to optimize processes around ordering and interpreting enhanced DATs.”

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The research team conducted a retrospective chart review to evaluate the volume of DATs at a large reference center in the United States and determine their impact on patient management.

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Enhanced DATs for 21 adult patients were sent for analysis between January 2019 and January 2021. Four of the 21 had positive initial DAT results, and enhanced DATs revealed an additional 5 patients, but were negative or invalid for 2 patients.

Among the 12 patients treated with high-dose corticosteroids before receipt of the enhanced DAT results, medical decision making was only affected in 3 patients. In the patients not treated with steroids, none were impacted by the enhanced DAT results.

The authors concluded that enhanced DATs do not generally impact medical decision making in patients with AIHA, and that there is an opportunity for pathologists to consult with clinicians regarding optimizing processes around ordering and interpreting these test results.


Thant M, Cancelas J, Kaplan A. The enhanced direct antiglobulin test in current practice has a limited impact on management of adult patients. Transfus Apher Sci. Published online August 17, 2023. doi:10.1016/j.transci.2023.103768