A 50-year-old male patient presented to an outpatient clinic in the spring of 2020 with fever and dyspnea; he told clinicians that the symptoms had persisted for the past 3 days.
Physical examination findings included a fever of 37.8°C (100°F), respiratory rate of 24 breaths/min, and heart rate of 105 beats/min. There was no organomegaly, and the patient was a non-smoker.
Initial laboratory test findings included:
- White blood cell count: 6.4 × 109/L
- C-reactive protein (CRP): 4.6 mg/L
- Ferritin: 162 ng/mL
- D-dimer: 842 ng/mL