Which test is used to confirm a diagnosis of influenza?

The rapid influenza nasal swab test is a diagnostic tool specifically designed to detect the presence of influenza virus in respiratory specimens. This test is beneficial because it can produce results within a short time, typically in about 15 to 30 minutes, allowing for quick confirmation of influenza infection. It works by identifying viral antigens in the nasal secretions, thus providing an effective means for both diagnosis and public health management during influenza outbreaks.

The other options are not suitable for confirming an influenza diagnosis. A CT scan is primarily used for imaging internal structures and is not designed for diagnosing viral infections. A complete blood count (CBC) provides information about blood cells and may indicate an infection but does not specifically diagnose influenza. A chest X-ray is often used to evaluate lung conditions, such as pneumonia, but it does not detect the influenza virus itself. Therefore, the rapid influenza nasal swab test stands out as the appropriate diagnostic tool for confirming influenza.