Abstract
Background:
Several erythrocyte antigens have been identified in canines, specifically in dogs, such as Dog Erythrocyte Antigen (DEA): 1, 3, 4, 5, 7; DAL, Kai 1, and Kai 2. Among these, only some are of significant clinical importance, while others require further research to determine their antigenic potential and the possible incompatibility reactions that could arise during transfusions. In Chile, only the DEA 1 is typed due to its high antigenic capacity and the risk of severe hemolytic reactions it can provoke; however, no frequency studies on this antigen have been conducted in the country. Additionally, there is limited information regarding possible associations between dog breed, health status, sex, and DEA1 expression.

Aim:
This study aimed to determine the frequency of DEA-1 expression in dogs from the Valparaíso region, Chile, and to assess its association with dog breed, health status, and sex.

Methods:
Data from Alvedia Quick Test BT DEA 1 immunochromatographic tests collected from February 2018 to September 2024 in three veterinary clinical laboratories in the Valparaíso region, Chile, were retrospectively analyzed. The frequency of DEA 1 expression was determined. Chi-square and Fisher’s exact tests were used to assess associations between breed, health status, sex, and DEA 1 expression.

Results:
The frequency of DEA-1 positivity was 64.97%. A statistically significant association was found between breed and DEA 1 expression (p = 0.006). However, no significant association was observed between DEA-1 expression and sex (p = 0.276) or health status (p = 0.494).

Conclusion:
In the Valparaíso region of Chile, the observed frequency of DEA 1 is similar to the globally reported rate (60%). Certain breeds of dogs are highly likely to express DEA 1, whereas others rarely do.

Key words: Blood typing; DEA 1; Dogs; Frequency.