Test Characteristics of the Anigen® Rapid AIV Ag Test (Avian Influenza Type A Rapid Antigen Test) in Ducks in Vietnam

The current study evaluated the test characteristics of a commercially available rapid antigen test (The Anigen® Rapid AIV Ag test) for Highly Pathogenic Avian Influenza (HPAI). Diagnostic specimens were collected from 175 ducks at markets and under controlled laboratory conditions in Vietnam. The relative diagnostic test sensitivity and the relative diagnostic test specificity were calculated by using real-time Reverse Transcription Polymerase Chain Reaction tests as the confirmatory diagnosis. The Anigen® Rapid AIV Ag test had a relative diagnostic sensitivity of 0.61 (95% confidence interval [CI] 0.45-0.75) and a relative diagnostic specificity of 0.98 (95% CI: 0.94–0.99). The result show that the Anigen® test can detect, with limited sensitivity, HPAI H5N1 clades circulating in Vietnam. The test can aid by making a differential diagnosis in sick or dying chickens, ducklings and adult ducks. Due to the limited sensitivity more birds may need to be tested to increase flock sensitivity. As flock prevalence of virus shedding ducks in Vietnam is low, this test is not suitable to reliably and quickly detecting Influenza A virus from apparently healthy ducks.