Rapid antibody test for diagnosing coccidioidomycosis in dogs

Abstract

Coccidioidomycosis in dogs can range from mild respiratory disease or vague, chronic malaise to acute, severe life-threatening illness. The diagnosis of coccidioidomycosis in dogs is based on clinical presentation and serology. Spherule identification is not typical because of low numbers of organisms in specimens, and the invasive nature of sampling tissues and lungs. Conventional serological assays require samples to be submitted to a reference laboratory and results take several days to one week. The sōna Coccidioides Antibody Lateral Flow Assay (LFA) (IMMY Diagnostics) is a rapid, bench-side test used for detection of Coccidioides antibodies that is available and FDA-cleared for use in humans but has not been evaluated in dogs. The goal of this study was to compare the LFA to conventional agar gel immunodiffusion (AGID). Paired serum samples were collected for screening by the LFA and submitted to a commercial reference laboratory for AGID screen and titer. Of 56 paired serum samples analyzed, 30 were positive and 26 were negative on the sōna Coccidioides antibody LFA. The overall percentage agreement plus 95% confidence interval (CI) was 87.5% (76.20-93.99). Positive percent agreement was 89.7% (73.38-96.65) and negative percent agreement was 85.2% (67.25-94.36). The kappa coefficient to assess agreement was 0.749 (95% CI, 0.576-0.923), which is interpreted as good agreement between the tests (>70%). The sōna Coccidioides antibody LFA provided rapid, point-of-care results with a high level of agreement to standard AGID serology in dogs clinically suspected to have coccidioidomycosis, and may aid in diagnosis of coccidioidomycosis in dogs.