Peripheral Blood Smear Findings in Sars-Covid-2 Infection

Abstract

Introduction

SARS-COV-2 is highly contagious enveloped single-stranded RNA virus that belongs to family Betacoronaviruses. The disease progresses from an upper respiratory tract infection with general flu-like symptoms to pneumonia and hyperinflammatory host reaction leading to acute respiratory distress and multiorgan failure. This study is to highlight the morphological changes observed in peripheral blood smears of COVID -19 positive cases.

Aims and Objectives

To evaluate the changes in Peripheral blood smears in COVID -19 positive patients like:

1. RBC morphology.


2. Platelet morphology.


3. WBC- morphological changes in granulocytes like toxic granules, vacuoles, apoptotic changes, shift to left (when immature granulocyte percent >5% & band forms >10%), Acquired Pleger-Huet anomaly (APHA) and presence of atypical lymphocytes.

Materials and Methods

Confirmed COVID-19 in-patient (IPD) cases whose samples were sent in Ethylenediamine tetra acetic acid (EDTA) vacutainers during the study period i.e, from May 1, 2020 to October 31, 2020 were included in this study.

Peripheral smears were stained with Wright stain and the manual differential count was performed along with that RBC, WBC and Platelet morphology were looked for in Peripheral blood smear.

Results

Among 650 COVID- 19 patient’s. Neutrophil toxic vacuoles and granules were seen in 414 cases (63.69%), Acquired Pleger-Huet Anomaly (APHA) in 241 cases (37%), Atypical lymphocytes in 186 cases (28.61%), giant platelets in 167 cases (25.69%) & 13 cases showed leucoerythroblastic reaction.

Conclusion

We conclude that careful examination of peripheral blood smears to be done in SAR-COV2 infection. Findings like toxic granules, vacuoles, apoptotic changes, shift to left, Acquired Pleger-Huet anomaly in neutrophils and atypical lymphocytes direct it towards COVID-19 infection & are also indicators of adverse clinical outcomes. Hence Peripheral blood smear finidngs can help pathologist to alert the physicians of impending severity.