COVID-19: laboratory diagnosis for clinicians. An updating article

Abstract

INTRODUCTION COVID-19 (coronavirus disease 2019) is an infectious disease caused by the new coronavirus associated with severe acute respiratory syndrome 2 (SARS-CoV-2). Coronaviridae comprises a large family, and at least seven coronaviruses are well known for causing respiratory diseases in humans. Coronaviruses have the ability to infect virtually all major groups of animals, among which some host other species that may infect humans. The current understanding is that SARS-CoV-2 is the third zoonotic coronavirus to have crossed the barrier between species and become capable of infecting humans over the past two decades. THE CORONAVIRUS THAT CAUSES COVID-19 SARS-CoV-2 is a new betacoronavirus belonging to the large viral family of Coronaviridae, first identified in an outbreak of pneumonia cases in Wuhan city, Hubei province, China, in December 2019. The name COVID-19 was chosen as the name for this new infection as an acronym of coronavirus disease 2019, i.e. from corona "co", virus "vi", disease "d" and the number 19 indicating the year of its appearance. Efforts are being made by the World Health Organization (WHO) to ensure that the nomenclature of viruses and their infections no longer refers to geographical locations, as it did traditionally, in order to combat the stigma resulting from this practice. The entire SARS-CoV-2 genome is inscribed on a single strand of RNA (ribonucleic acid). This type of virus undergoes genetic mutations more frequently than DNA (deoxyribonucleic acid) viruses, given that RNA viruses have less ability to correct any transcription errors. 1 SARS-CoV-2, in particular, is a single-stranded RNA virus that is capable of synthesizing about 29 different proteins. Some of these proteins are present on the surface of the virus and act as facilitators of its entry into host cells, while others, apparently, are related to its pathogenesis. Characteristically, coronaviruses are responsible for respiratory infections in humans and some animals. Most of the time, the infections caused by viruses in this family are mild to

Laboratory diagnosis of COVID-19

“… 3 One example is the qualitative detection of the E and N proteins genes through the GeneXpert (Cepheid Company) platform, in which the amplification process takes place within a cartridge and provides results in 45 min. 20 …”

“…Point-of-care tests for antibodies against SARS-CoV-2 using lateral flow assays (usually immunochromatography) are quite numerous and many of them have not been adequately validated. 20 Moreover, they were tested in the laboratory using plasma or serum, but have been applied with whole blood, which can greatly modify their sensitivity. 21 They are not recommended to be used for the individual diagnosis of COVID-19, but may be useful in implementing public policies.…”

Associação dos principais parâmetros hematológicos, bioquímicos e imunológicos em pacientes graves e não graves com COVID-19: uma revisão sistemática

“…A linfopenia causada pela COVID-19 vem sendo observada como uma predição laboratorial complementar fundamental, principalmente direcionado ao prognóstico do paciente, todavia, a relação de neutrófilos/linfócitos e plaquetas/linfócitos também podem auxiliam na análise da condição clínica da gravidade dos pacientes. Na decorrência da doença, avaliações de parâmetros laboratoriais inflamatórios como: LDH, PCR e IL-6 contribuem para o reconhecimento de casos com piores prognósticos, onde os pacientes precisam de condutas terapêuticas com intervenção mais agressiva (Vieira et al, 2020).…”

“…Um ponto interessante corresponde às transaminases hepáticas. Estas como biomarcadores podem se elevar com a hipóxia causada pela pneumonia viral do SARS-CoV-2, resultando em uma elevação de ALT e AST e indicando um significativo sofrimento em células hepáticas, comprometendo o quadro clínico do paciente (Vieira et al, 2020).…”

Obtaining tissues and organs for transplantation and coronavirus infections: a scoping review

“…In Brazil, carrying out the molecular biology test to detect viral RNA has also become a necessity for the continuity of solid organ transplants. However, especially in the first weeks after the decreed community transmission of COVID-19, there was a limitation in the availability of tests (16)(17) . In our daily practice with the organ and tissue donation process, at the beginning of the pandemic, there were moments of scarcity of kits to test all potential donors.…”