Diagnostic value of peripheral hematologic markers for coronavirus disease 2019 (COVID-19): A multicenter, cross-sectional study

J Clin Lab Anal. 2020 Oct;34(10):e23475. doi: 10.1002/jcla.23475. Epub 2020 Jul 17.


Background: To determine the diagnostic value of hematologic markers for coronavirus disease 2019 (COVID-19) and explore their relationship with disease severity.

Methods: Subjects included 190 COVID-19 patients, 190 healthy subjects, and 105 influenza pneumonia (IP) patients. COVID-19 patients were divided into the ARDS and non-ARDS groups. Routine blood examination, biochemistry indicator, days in hospital, body temperature, pneumonia severity index (PSI), CURB-65, and MuLBSTA were recorded. Correlations between variables were assessed using Spearman's correlation analysis. Receiver operating characteristic (ROC) curves were used to study the accuracy of the various diagnostic tests.

Results: Compared with healthy subjects, COVID-19 patients had lower white blood cell (WBC), lymphocyte, platelet, and hemoglobin levels; higher percentages of neutrophils and monocytes; lower percentages of lymphocytes and higher neutrophil-to-lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio (MLR), and platelet-to-lymphocyte ratio (PLR) values (P < .05). COVID-19 patients had higher WBC and neutrophil levels and lower percentages of lymphocytes compared to IP (P < .05). ROC curve analysis revealed that MLR had a high diagnostic value in differentiating COVID-19 patients from healthy subjects, but not from IP patients. NLR showed significant positive correlations with PSI, CURB-65, and MuLBSTA. Lymphocyte count was lower in the ARDS group and yielded a higher diagnostic value than the other variables.

Conclusions: Monocyte-to-lymphocyte ratio showed an acceptable efficiency to separate COVID-19 patients from healthy subjects, but failed to rule out IP patients. NLR may be a reliable marker to evaluate the disease severity of COVID-19. Lymphocyte count may be useful to establish the early diagnosis of ARDS in the COVID-19 patients.

Keywords: coronavirus disease 2019; diagnostic value; lymphocyte; monocyte-to-lymphocyte ratio; neutrophil-to-lymphocyte ratio.

Publication types

  • Multicenter Study

MeSH terms

  • Adult
  • Betacoronavirus
  • Biomarkers
  • COVID-19
  • COVID-19 Testing
  • Clinical Laboratory Techniques* / methods
  • Clinical Laboratory Techniques* / standards
  • Coronavirus Infections* / blood
  • Coronavirus Infections* / diagnosis
  • Coronavirus Infections* / epidemiology
  • Cross-Sectional Studies
  • Female
  • Humans
  • Leukocyte Count*
  • Lymphocytes / cytology
  • Male
  • Middle Aged
  • Monocytes / cytology
  • Neutrophils / cytology
  • Pandemics*
  • Pneumonia, Viral* / blood
  • Pneumonia, Viral* / diagnosis
  • Pneumonia, Viral* / epidemiology
  • Predictive Value of Tests
  • SARS-CoV-2


  • Biomarkers