Influenza virus causes significant morbidity and mortality each season. This is especially true in restricted populations like nursing homes and other institutions. Since antiviral treatment is available for Influenza type A and the agent is readily transmitted, prompt and accurate diagnosis is essential for patient treatment and infection control. Influenza viruses are traditionally identified directly by fluorescent antibody (DFA) or by initial isolation in cell culture with subsequent identification. Conventional culture is the gold standard but takes between 3-7 days after a series of susceptible cells is inoculated with a virus specimen from the appropriate transport medium. This method uses a cell culture using two different cell lines in a single cell well. Upon inoculation, the mixed cell culture is incubated for 24 hours and subsequently blind stained by IFA using strain specific monoclonal antibody.