Coronavirus disease 2019 (COVID-19) is associated with various symptoms and changes in hematological and biochemical variables. However, clinical features, which can differentiate
COVID-19 from non-COVID-19, are not clear. We therefore examined the key clinical features of
COVID-19 and non-COVID-19 patients. This study included 60
COVID-19 patients and 100 non-COVID-19 patients, diagnosed by PCR, and no significant differences in the age and sex were seen between the two groups. The frequencies of
fatigue, loose stool,
diarrhea,
nasal obstruction, olfactory
dysfunction, taste dysfunction, underlying
hyperlipidemia, and the prescription of
angiotensin II receptor blocker (ARB) were significantly higher in
COVID-19 patients than those in non-COVID-19 patients. The counts of leucocytes, neutrophils, lymphocytes, eosinophils, monocytes, and basophils and the levels of
chloride and
calcium in blood of
COVID-19 patients were significantly lower than those of non-COVID-19 patients. The frequencies of atypical lymphocytes and the levels of
lactate dehydrogenase (LDH) and
potassium were significantly higher in
COVID-19 than those in non-COVID-19. The
C-reactive protein (CRP) level in
COVID-19 patients was significantly lower than that in non-COVID-19 patients, when we compared CRP levels among patients with elevated CRP. This study is the first to indicate that
electrolyte levels and the frequency of atypical lymphocytes in
COVID-19 are significantly different from those in non-COVID-19.
Fatigue, loose stool,
diarrhea,
nasal obstruction, olfactory dysfunction, and
taste dysfunction were the key symptoms of
COVID-19. Furthermore,
hyperlipidemia and ARB may be risk factors of
COVID-19. In conclusion, leucocytes, leucocyte fractions, CRP, LDH, and
electrolytes are useful indicators for
COVID-19 diagnosis.