Until quite recently, physicians and patients alike need a clear answer to the question:  "is it just a cold, or is it the flu?"

The emergence of COVID-19 has changed the conversation.

"Is it the flu, or is it COVID?" Although there are key differences between the two, flu and COVID-19 share many superficial characteristics. Fever, cough, difficulty breathing, and fatigue are symptoms commonly associated with both diseases. These similarities mean symptoms alone offer physicians little guidance.

To complicate the matter furthermore, undiagnosed co-infection with respiratory pathogens, such as COVID-19 and bacterial pneumonia, can develop into acute respiratory distress syndrome (ARDS). The diagnosis and subsequent therapeutic response differ significantly depending on which infections are identified. For these reasons, testing may be needed to help confirm a diagnosis and provide insight into the best path for treatment.