Methods
Children admitted to the Emergency Department of Ministry of Health
Ankara City Hospital Children’s Hospital, which is a tertiary children
hospital with 555 beds capacity, with symptoms including fever, sore
throat, rhinorrhea, cough between 1-15 April 2020, were included in the
study. All patients were tested for SARS-CoV-2 by quantitative real-time
reverse transcription polymerase chain reaction from combined nasal and
oropharyngeal swab samples. Complete blood count test and peripheral
smear were done on admission of Emergency Department. Patients unable to
obtain peripheral blood smear were excluded from the study. Thirty
children were tested to be positive for SARS-CoV-2 and the remaining 40
symptomatic children were tested to be negative.
Complete blood count (CBC) was analyzed with Siemens ADVIA 2120i
Hematology Analyzer with Auto slide (Siemens Healthcare Diagnostics,
Erlangen, Germany); CBC results, including differential count results,
were noted. Estimated absolute lymphocyte (ALC), neutrophil (ANC),
monocyte (AMC) counts, were recorded from CBC results and were also
calculated from peripheral smear specimens. Hemoglobin, leukocyte and
neutrophil values were assessed according to age-specific intervals
(16); ALC<3x109/L and ALC
<1.5x109/L were accepted as lymphopenia in
<12-month and >12-month old patients,
respectively (16). Neutropenia was diagnosed with an absolute neutrophil
count of <1.5x109/L (16).
Neutrophil/lymphocyte ratio was calculated by the ADVIA 2120i analyzer.
C-reactive protein values were also recorded.
All patients’ peripheral blood smear specimens (May-Grünwald-Giemsa
stain x100) were evaluated for neutrophil, thrombocyte and erythrocyte
morphology and differential counts were formulated by manual counting
including reactive lymphocyte and immature myeloid cells (band,
metamyelocyte and myelocyte). the peripheral smears was blindly
evaluated to the SARS-CoV-2 test result. The correlation between the
reactive lymphocyte count in manual peripheral smear and large unstained
cells (LUC), which reflects the activated lymphocytes and
peroxidase-negative cells as measured by ADVIA 2120i, was analyzed.
Moreover, the correlation between the percentage of immature myeloid
cells in peripheral smear and delta neutrophil index (DNI) was assessed;
DNI reflects immature myeloid cells and is calculated by subtracting
polymorphonuclear leukocyte count in nuclear lobularity channel from
neutrophil and eosinophil count in myeloperoxidase channel, both
measured by the ADVIA 2120i analyzer.
The data were expressed as mean ±SD. Student’s t-test was used to
compare the means. Pearson correlation was used to assess the
relationship between two quantitative, continuous variables. A value of
p<0.05 was considered significant.