ABSTRACT. do Couto M.C.M., Silva V.L., Pinheiro J. & do Bomfim T.C.B. Enzyme immunoassay use in the identification of Giardia spp. in Perna perna mussels destined for human consumption. [Utilização do Ensaio Imunoenzimático no Diagnóstico de Giardia spp. em Moluscos Perna perna Destinados ao Consumo Humano.] Revista Brasileira de Medicina Veterinária, 38(supl. 3):8-15, 2016. Programa de Pós-Graduação em Ciências Veterinárias, Anexo 1, Instituto de Veterinária, Universidade Federal Rural do Rio de Janeiro, BR 465 - Km 7, Seropédica, RJ 23890-000, Brasil. E-mail: email@example.com Marine bivalve molluscs are important due to the expansion of mariculture and because they are considered bioindicators of environmental pollution. Bivalve molluscs are capable of filtering large volumes of water and can accumulate waterborne pathogens, such as cysts of Giardia intestinalis, especially in their gills and digestive gland. Thus, the ingestion of raw or undercooked molluscs can be a potential source of human infection. This study aimed to use the enzyme-linked immunosorbent assay (ELISA) technique to detect cysts of Giardia spp. in tissues of mussels of the species Perna perna destined for human consumption in the coast at the Municipality of Mangaratiba in the State of Rio de Janeiro, Brazil. Each sample was prepared from a pool of 10 animals, totalling 72 samples of mussel tissue that were evaluated for the presence of Giardia spp. by ELISA. For sampling, only individuals with an average of 6 cm of valve length were analyzed, which is considered the ideal size for consumption. In each sample, the individuals were dissected, and only the gills and digestive gland were used, which were homogenized with the aid of a mixer and filtered to remove coarse residues. The use of the enzyme kit followed the recommendations of the manufacturer with minor modifications. Among the 72 samples used, only 22% were positive for the presence of Giardia spp. antigens. The obtained results were evaluated by colorimetry and by an ELISA plate reader with a 450/630 nm filter. Based on the results, the authors suggest that the use of the immunoassay kit is effective in the diagnosis of Giardia spp. and could be considered a screening method prior to analysis by other diagnostic methods.