Peripheral Blood Examination Findings in SARS-CoV-2 Infection

Alia Nazarullah, Christine Liang, Andrew Villarreal, Russell A. Higgins, Daniel D. Mais

Research output: Contribution to journalArticlepeer-review

37 Scopus citations


Objectives: Peripheral blood abnormalities in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have not been fully elucidated. We report qualitative and quantitative peripheral blood findings in coronavirus disease 2019 (COVID-19) patients and compare them with a control group. Methods: We reviewed electronic medical records, complete blood counts, peripheral blood smears, and flow cytometry data in 12 patients with SARS-CoV-2. These were compared with 10 control patients with symptoms suspicious for SARS-CoV-2 but who tested negative. Results: No significant differences were noted in blood counts, except that absolute lymphopenia was present frequently in the control group (P < .05). Acquired Pelger-Huët anomaly (APHA) was noted in all COVID-19 cases, in most cases affecting over 5% of granulocytes. This contrasted with APHA in only 50% of control cases, affecting fewer than 5% of granulocytes in all cases (P < .05). Monolobate neutrophils were exclusive to COVID-19 cases. COVID-19 patients had greater frequency of plasmacytoid lymphocytes (P < .05). Flow cytometry data revealed absolute CD3+ T-cell count reduction in 6 of 7 patients; all of them required mechanical ventilation. Conclusions: Lymphopenia was infrequent in our COVID-19 cohort; however, flow cytometric analysis revealed absolute T-cell count reduction in most cases. COVID-19 cases had significant APHA with monolobate neutrophils and plasmacytoid lymphocytes as compared to controls.

Original languageEnglish (US)
Pages (from-to)319-329
Number of pages11
JournalAmerican journal of clinical pathology
Issue number3
StatePublished - 2020


  • COVID-19
  • Coronavirus
  • Hematologic
  • Peripheral blood
  • Peripheral smear
  • SARS-CoV-2

ASJC Scopus subject areas

  • Pathology and Forensic Medicine


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