COVID‐19 and the clinical hematology laboratory

Abstract

The ongoing COVID-19 pandemic originated in Wuhan, Hubei Province, China in December 2019. The etiologic agent is a novel coronavirus of presumed zoonotic origin with structural similarity to the viruses responsible for severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS). Like SARS and MERS, COVID-19 infection manifests most frequently with lower respiratory symptoms. A minority of patients progress to acute respiratory distress syndrome/ diffuse alveolar damage. In addition to its central role in the diagnosis of COVID-19 infection, the clinical laboratory provides critical information to clinicians regarding prognosis, disease course, and response to therapy. The purpose of this review is to 1) provide background context about the origins and course of the pandemic 2) discuss the laboratory's role in the diagnosis of COVID-19 infection 3) summarize the current state of biomarker analysis in COVID-19 infection, with an emphasis on markers derived from the hematology laboratory 4) comment on the impact Accepted Article of COVID-19 on hematology laboratory safety, and 5) describe the impact the pandemic has had on organized national and international educational activities worldwide.

Complete blood counts and cell population data from Sysmex XN analyser in the detection of SARS-CoV-2 infection

“…Conditions such as neutrophilia, lymphopenia and thrombocytopaenia and changes in the levels of markers of systemic inflammation (e.g., neutrophil-to-lymphocyte ratio, NLR), are the most significant quantitative alterations. They have been recognised as valid predictors of disease severity [4,5]. Morphological anomalies of circulating blood cells have also been reported in COVID-19 [6].…”

Overwhelming COVID-19 Sepsis in a Patient With Idiopathic Pulmonary Fibrosis

“…Severe sepsis is marked by organ dysfunction due to poor blood flow (eg oliguria from poor renal perfusion and altered mental status from poor cerebral perfusion). His laboratory studies showed a consumptive coagulopathy (thrombocytopenia, prolonged PT/aPTT), which, along with bleeding from the IV catheter site and elevated D-dimer, was likely due to DIC [7].…”

COVID-19 and Systemic Lupus Erythematosus: Focus on Immune Response and Therapeutics

“…Whatever the cause, lymphopenia is an important factor often associated with SLE patient susceptibility to bacterial and viral infections (33)(34)(35). Interestingly, many COVID-19 patients without SLE exhibit lymphopenia (36). 35-75% (studydependent) of patients who have COVID-19 develop lymphopenia, defined as a lymphocyte count of <1.5 x 10^9/L (37).…”

“…35-75% (studydependent) of patients who have COVID-19 develop lymphopenia, defined as a lymphocyte count of <1.5 x 10^9/L (37). Additionally, this clinical finding is a more common feature in patients who died from COVID-19 (36). Furthermore, there seems to be a geographical difference in lymphopenia rates.…”

“…More patients in Italy show lymphopenia when compared to places like Singapore and the Zhejiang Province. There are many reasons why this may happen, but one theory is that the viral genome has mutated and is sparking different immune responses as a result of those mutations (36). Overall, a decrease in the number of B and T cells may lead to a worse patient outcome if their ability to fight off the virus is diminished.…”