Comparison of Three Serologic Tests for the Detection of Anti-Coxiella burnetii Antibodies in Patients with Q Fever
Danilo Alves de França, Mateus de Souza Ribeiro Mioni, Felipe Fornazari, Nássarah Jabur Lot Rodrigues, Lucas Roberto Ferreira Polido, Camila Michele Appolinário, Bruna Letícia Devidé Ribeiro, Ana Íris de Lima Duré, Marcos Vinicius Ferreira Silva, Virgínia Bodelão Richini‐Pereira, Hélio Langoni, Jane Megid
Abstract
The performance of a commercial immunofluorescence assay (IFA commercial), an in-house immunofluorescence assay (IFA in-house) and an indirect enzyme-linked immunosorbent assay (ELISA) were evaluated in the detection of antibodies anti-C. burnetii in the serum of Q fever patients and persons without the disease. For the study, seropositive and seronegative samples for Q fever (n = 200) from a serum bank of the Instituto Adolfo Lutz in Brazil were used. Commercial IFA was considered in this study as the gold standard for diagnosing Q fever. The in-house IFA demonstrated good agreement with the commercial test, showing high sensitivity (91%) and specificity (97%) compared to the gold standard, with a Kappa coefficient of 0.8954. The indirect ELISA test showed lower agreement with the gold standard, showing low sensitivity (67%), although the specificity of the technique was high (97%) and the Kappa coefficient was moderate (0.6631). In-house IFA is an excellent alternative for diagnosing Q fever.