Laboratory findings in SARS-CoV-2 infections: State of the art

The scientific community is constantly assessing the clinical and laboratory manifestations of COVID-19 in the organism. In view of the fragmentation of the large amount of information, knowledge gaps in relation to laboratory markers, and scarcity of papers in Portuguese, we propose a Literature review on laboratory changes observed in patients infected with SARS-CoV-2.

Analysis of articles published between December 2019 and May 2020 on the PubMed and SciELO databases. The articles were identified, filtered, and evaluated based on the approach to the subject, language, and impact. Then, the articles were subjected to a thorough reading, in full, by 4 (four) independent researchers.

Leukopenia and lymphopenia were included in most studies, even in case definitions. Platelet count and platelet-lymphocyte ratio, at peak platelet, were associated with advanced age and longer hospital stay. Eosinopenia showed a sensitivity of 74.7% and specificity of 68.7% and, together with increased CRP, these are one of the future prospects for screening for disease. A high level of procalcitonin may indicate bacterial co-infection, leading to a worse prognosis. COVID-19 manifests itself with increased levels of many inflammatory markers such as IL-1, IL-2, IL-6, IL-7, IL-12, IP10, IFN-γ, MIP1A, MCP1, GSCF, TNF-α, and MCP1/CCL2, as well as LDH, ESR, D-dimer, CK, ALT, and AST.

There is a need for further studies on the new SARS-CoV-2. So far, there is no consensus regarding laboratory findings and their usefulness, whether as a prognostic marker, mortality, or disease severity.