Patient Sampling  Purpose: diagnosis COVID‐19 pneumoniaDesign: cross‐sectional, retrospective, single‐centre studyRecruitment: patients admitted to ED with history of exposure to COVID‐19Sample size: n = 132 (cases = 7)inclusion criteria: all patients admitted to the fever clinic of the ED of the First medical center, Chinese People's Liberation Army General Hospital (PLAGH) in Beijing with the epidemiological history of exposure to COVID‐19 according to WHO interim guidanceExclusion criteria: < 14 years old, no other criteria specified