Influenza

Influenza virus can be readily isolated from nasal swabs, throat swabs, nasal washes, and sometimes sputum. A throat swab alone is less sensitive than nasal or throat washes, and thus washes are preferred. Specimens should be placed into containers of viral transport medium and transported to the laboratory for viral culture. Two-thirds of positive cultures will be detected within seventy-two hours, with the remainder within five to seven days. However, particularly for influenza detection in long-term care facilities, faster methods of detection are needed. A variety of rapid detection methods for influenza virus exist that detect viral antigens by immunofluorescence or ELISA in as little as one hour, with reasonable sensitivity and specificity under optimal conditions. At present though, viral culture remains the gold standard for diagnosis of influenza infection.