The medical laboratory prosecution of Covid – 19: pathogenesis and diagnosis

Abstract

The outbreak of Covid – 19 is now a pandemic affecting population pan continentally. It has challenged the health system at various levels such as case identification, diagnostic laboratory workup, management and treatment and the epidemiological aspects of preventive interventions. It is so because this viral infection has never ever been encountered in past. The coronavirus is a single stranded RNA virus with a few peculiarities of structure such as spike glycoprotein (S). This structural protein has been attributed to pathogenesis of Covid – 19 infections. The transmission of Covid - 19 is by droplets and aerosol. It primarily affects lungs, and its binding sites are cellular receptor of ACE II of pneumocytes. The morbidities and fatalities associated to Covid-19 infection are attributed to cytokine storm. It chiefly affects lungs producing pneumonitis. There are other manifestations of Covid – 19 infections. The diagnosis of Covid – 19 infection is by PCR of nasopharyngeal swab and samples from trachea and bronchi. The antibody (IgM and IgG) testing too is advised but as a auxiliary methods in support of diagnosis.The hematological manifestations and biochemistry of the blood helps in suspecting and predicting the course of Covid – 19 infection. The present review imbibes within it, the various scientific nuances of novel corona virus that introduces Covid -19 infection and explains the characteristics of the virus, pathogenesis and cytokine storm, immune evasion, lung injury, histological alteration, laboratory diagnosis, biosafety, parameters of significance in laboratory ,rRT-PCR of viral RNA and the proposed model of laboratory evaluation of Covid – 19 infection. The review provides a model for resource limited hospital at screening and confirmation of Covid – 19 infections which will simplify, augment and enable the necessary hospital services and corrective therapeutic interventions.