Overview of the Haematological Effects of COVID-19 Infection

Coronavirus disease 2019 (COVID-19): Focus on peripheral blood cell morphology

Numerous studies have shown peculiar morphological anomalies in COVID-19 patients' smears. We searched all the peer-reviewed scientific publications that explicitly reference the cytomorphological alterations on peripheral blood smears of patients with COVID-19. We extracted data from sixty-five publications (case reports, patient group studies, reviews, and erythrocyte morphology studies). The results show that frequent alterations concern the morphology of lymphocytes (large lymphocytes with weakly basophilic cytoplasm, plasmacytoid lymphocytes, large granular lymphocytes). Neutrophils display abnormal nuclei and cytoplasm in a distinctive cytomorphological picture. Besides a left shift in maturation, granulations can be increased (toxic type) or decreased with areas of basophilia. Nuclei are often hyposegmented (pseudo-Pelger-Huёt anomaly). Apoptotic or pycnotic cells are not uncommon. Monocytes typically have a large cytoplasm loaded with heterogeneous and coalescing vacuoles. Platelets show large and giant shapes. The presence of erythrocyte fragments and schistocytes is especially evident in the forms of COVID-19 that are associated with thrombotic microangiopathies. Such atypia of blood cells reflects the generalized activation in severe COVID-19, which has been demonstrated with immunophenotypic, molecular, genetic, and functional methods. Neutrophils, in particular, are involved in the pathophysiology of hyperinflammation with cytokine storm, which characterizes the most unfavorable evolution.

Hematological findings in adult patients with SARS CoV‐2 infection at Tygerberg Hospital Cape Town South Africa

Background

Coronavirus disease 2019 (COVID‐19) is associated with hematological abnormalities of variable severity. The full blood count (FBC) and leukocyte differential count (DIFF) could facilitate the prediction of disease severity and outcome in COVID‐19. This study aimed to assess the hematological parameters in early severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection and their correlation with disease outcome.

Methods

A retrospective cross‐sectional descriptive study was performed. Adults with a FBC and positive SARS‐CoV‐2 polymerase chain reaction results between March 1, and June 31, 2020 were reviewed. Basic hematological parameters (FBC, DIFF) and human immunodeficiency virus (HIV) status were recorded. Outcome measures were admission to a general ward or intensive care unit (ICU), recovery or death.

Results

Six hundred and eighty‐five cases median age 51 years, were analyzed. Forty‐four percent were males and fourteen percent were HIV‐positive with no association between death and/or ICU admission (p = 0.522 and p = 0.830, respectively). Leucocytosis was predictive of ICU admission (odds ratio [OR]: 2.4, confidence interval [CI]: 1.77–3.8186) and neutrophilia, of both mortality (OR: 1.5, CI: 1.0440–2.0899) and ICU admission (OR: 4, CI: 2.5933–6.475). Median lymphocyte count was decreased and d‐dimer raised, showing no significant association with outcome. Raised neutrophil‐to‐lymphocyte‐ratio (NLR) was associated with increased odds of mortality (OR: 2.5, CI: 1.3556–3.2503) and ICU admission (OR: 4.8, CI: 2.4307–9.5430) as was monocyte‐to‐lymphocyte‐ratio (MLR) (OR: 2, CI: 1.3132–2.9064) and (OR: 2.3, CI: 1.0608–1.9935), respectively. Hospital admission and older age were significantly associated with mortality (p = 0.0008 and p < 0.0001), respectively.

Conclusion

Evidence‐based interpretation of routine laboratory parameters, readily available in resource‐constrained settings, may identify patients at increased risk of mortality. The FBC, DIFF, NLR, and MLR should form part of the early COVID‐19 investigation.

Lab-on-a-Chip Immunoassay for Prediction of Severe COVID-19 Disease

Most people infected by the SARS-CoV-2 virus which causes COVID-19 disease experience mild or no symptoms. Severe forms of the disease are often marked by a hyper-inflammatory response known as a cytokine storm. Thus, biomarker tests which can identify these patients and place them on the appropriate treatment regime at the earliest possible phase would help to improve outcomes. Here we describe an automated microarray-based immunoassay using the Fraunhofer lab-on-a-chip platform for analysis of C-reactive protein due to its role in the hyper-inflammatory response.

The role of laboratory biomarkers in diagnostics and management of COVID-19 patients

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of a highly transmittable and heterogenic infection of the respiratory tract, characterized by a broad spectrum of clinical manifestations with a different degree of severity. Medical laboratories play an important role in early diagnosis and management of Coronavirus Disease 2019 (COVID-19) patients. Indeed, the results of several laboratory tests are essential for assessing the severity of the disease, selecting appropriate therapeutic procedures and monitoring treatment response. Routine laboratory testing in COVID-19 patients includes biomarkers of acute phase reaction, hematological and biochemical parameters that indicate tissue injury. The aim of this review paper is to describe the role of these biomarkers in the diagnostics and management of adult and pediatric COVID-19 patients.