Historically DEA 1 was considered to have 3 subgroups and the terminology DEA 1.1, 1.2 and 1.3 was used. With the development of monoclonal antibody and immunofluorescence testing, it has been found that DEA 1.2 and 1.3 are actually red cell populations with a lower density of the DEA 1 antigen on their surface. Testing allows for detection of low level DEA 1 which means an individual canine patient is now only either DEA 1 positive or negative (Acierno et al, 2014).
The full reference is: Acierno MM, Raj K and Giger U (2014) DEA 1 expression on dog erythrocytes analyzed by immunochromatographic and flow cytometric techniques. J Vet Intern Med 28(2):592-8
This is the hyperlink to the free online copy of this article https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3998747/
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