Although a diagnostic test is available for PCR testing of the virus by nasopharyngeal swab, there are cases in which clinical features are apparent, but a swab test may be negative, including cough, shortness of breath, temperature, often accompanied by laboratory changes such as lymphopenia, raised serum C-Reactive Protein (CRP), ferritin levels and pulmonary infiltrates on chest radiographs. This evidence concerns the gene CRP and lymphopenia.