The goal of this observational study is to compare the results of a serum biomarker called the MeMed BV®, which is approved to help differentiate between bacterial and viral respiratory infections, to clinical diagnoses of adult emergency department patients presenting with recent fever and signs or symptoms of a respiratory infection. Active participation is completed during the emergency department visit and includes drawing blood, obtaining a sputum sample, and answering survey questions.

The MeMed BV® is a diagnostic test newly approved by the FDA to assess the likelihood of bacterial vs. viral respiratory infections based on protein biomarkers in blood. This study aims to identify the level of agreement between the results of the MeMed BV® (bacterial/viral) and the standard of care treatment received by the participant (e.g. antibiotics for patient diagnosed with bacterial pneumonia) in order to see if implementing the MeMed BV® into standard clinical care would potentially change diagnosis.

Inclusion Criteria:

• Adults presenting to the emergency department
• Subjective or objective fever within the past 7 days
• Signs or symptoms of upper or lower respiratory tract infection within the past 7 days

Exclusion Criteria:

• Prisoner
• Suspicion and/or confirmed diagnosis of infectious gastroenteritis/colitis
• Active inflammatory disease
• Congenital or acquired immune deficiency
• Chronic fungal or parasitic infection
• Infection with human immunodeficiency virus (HIV)
• Hepatitis B virus (HBV)
• Hepatitis C virus (HCV)
• Infection with active tuberculosis (TB)
• Significant trauma or burns in the last 7 days
• Patients that have undergone major surgery in the last 7 days
• Pregnancy
• Active malignancy

Adults presenting to the ED with history of recent fever and signs or symptoms of acute respiratory infection.