Coccidioides is a genus of fungi that includes two main species: Coccidioides immitis and Coccidioides posadasii. These fungi are responsible for causing a respiratory infection known as coccidioidomycosis or Valley fever. Coccidioidomycosis is predominantly found in arid regions of the Americas, particularly the southwestern United States and parts of Mexico and Central America.

The ID assay for Coccidioides is specifically designed to detect and quantify Coccidioides-specific antigens in patient samples. It operates on the principle of immunodiffusion, which involves the formation of visible precipitin lines when an antigen and its corresponding antibody react in a gel medium. In this context, the assay employs specific antibodies that bind to Coccidioides antigens, resulting in the formation of characteristic precipitin lines.

The ID assay for Coccidioides presents several advantages. It is relatively straightforward to perform and does not require sophisticated equipment, making it accessible to laboratories with limited resources. It provides qualitative and semi-quantitative results, facilitating the detection and monitoring of Coccidioides infections. Furthermore, the assay can be employed as a diagnostic tool to assess the efficacy of antifungal therapies by measuring changes in antigen levels over time.