Low leukocyte and neutrophil counts are markers of COVID-19 infection

Objectives:
What are common laboratory parameters for coronavirus disease 2019 (COVID-19) case detection?

Study design:
This review article included 26 studies.

Heterogeneity was considerably high in all parameters measured (I2 = between 67 and 90%).

Begg's funnel plot and Egger's test were performed revealing no publication bias.

Results and conclusions:   
The investigators found 7 studies in the first analysis showed significantly lower leukocyte, neutrophil and platelet counts in COVID-19 pneumonia [SMD = -0.42, 95% CI = -0.60 to -0.25, p 0.00001, SMD = -0.23, 95% CI = -0.41 to -0.06, p = 0.01 and SMD = -0.54, 95% CI = -0.91 to -0.16, p = 0.0005] compared to non-COVID-19 pneumonia.

The investigators found 26 studies in the second analysis showed significantly lower lymphocyte and thrombocyte counts [SMD = -0.56, 95% CI = -0.71 to -0.40, p 0.0001, SMD = -0.32, 95% CI = -0.49 to -0.15, p = 0.0002] and significantly higher leukocyte, neutrophil, D-dimer and CRP [SMD = 0.31, 95% CI = 0.07 to 0.56, p = 0.01, SMD = 0.44, 95% CI = 0.24 to 0.64, p 0.0001, SMD = 0.53, 95% CI = 0.31 to 0.75, p 0.00001, SMD = 0.97, 95% CI = 0.70-1.24, p 0.00001] in severe COVID-19 compared to non-severe COVID-19.

The investigators concluded thrombocyte count is key in both diagnosis and prognosis. Low leukocyte and neutrophil counts are markers of COVID-19 infection, but contrastingly higher counts indicate progressive COVID-19. And although lymphocyte, D-dimer and CRP levels do not demonstrate diagnostic value, all indicate severity of COVID-19. Confirmation of these findings should be performed in future studies.

Original title:
Crucial Laboratory Parameters in COVID-19 Diagnosis and Prognosis: An Updated Meta-Analysis by Soraya GV and Ulhaq ZS.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7274591/

Additional information of El Mondo:
Find more information/studies on coronavirus right here.