the technique used in the diagnosis of covid-19 diagnosis
Answers
Answer:
Explanation:
Detection of SARS-CoV2 RNA in respiratory samples is the reference and choice technique for the microbiological diagnosis of COVID-19.
Advantages
It is the one with the highest sensitivity and specificity to detect the presence of viruses.
Viral RNA can be detected two days before symptoms appear; after the first symptoms, the viral load increases progressively in the acute phase, to subsequently decrease and become undetectable after 14-21 days.
In clinically severe cases, the PCR can remain positive for up to 30 days.
It allows to detect the presence of asymptomatic patients.
Confirms virus clearance in patients who have had COVID-19.
Inconvenient
It is a laborious technique and a laboratory equipped with a level 2 Biosafety room, special equipment and specialized staff is needed.
Explanation:
The COVID-19 pandemic, caused by the SARS-CoV-2 virus, has led to more than three million confirmed cases, with over 211,000 deaths globally, as of April 27, 2020. The living and working conditions of billions of people worldwide have been significantly disrupted due to different forms of social distancing and lockdowns in many cities. The world economy has been remarkably weakened as a result of business shutdowns and major restrictions on travel. Widespread availability of accurate and rapid testing procedures is extremely valuable in unraveling the complex dynamics involved in SARS-CoV-2 infection and immunity. To this end, laboratories, universities, and companies around the world have been racing to develop and produce critically needed test kits.
One of the many challenges for containing the spread of COVID-19 is the ability to identify asymptomatic cases that result in spreading of the virus to close contacts. A study of the passengers on a Diamond Princess Cruise ship forced into temporary quarantine from an early outbreak of COVID-19, estimated the asymptomatic proportion (among all infected cases) at 17.9% (95%CrI: 15.5–20.2%).1 Therefore, the actual number of SARS-CoV-2-infected individuals may be much higher than currently accounted for based on positive test results.2 Having accurate, convenient, and rapid testing for widespread deployment can aid in eliminating the silent spread of COVID-19 by asymptomatic viral carriers.
Because COVID-19 exhibits a range of clinical manifestations, from mild flu-like symptoms to life-threatening conditions, it is important to have efficient testing during the early stages of infection to identify COVID-19 patients from those with other illnesses. This avoids unnecessary quarantines of negative individuals and the spread of infection by positive individuals. Early diagnosis permits physicians to provide prompt intervention for patients who are at higher risk for developing more serious complications from COVID-19 illness. More complicated diagnostic testing based on viral genomic sequencing is an essential tool for determining the rate and degree of mutational variability associated with SARS-CoV-2 and for identifying newly emerging strains of the virus for more effective vaccine development. Until a commercial vaccine becomes available, it is important to identify individuals who have been infected with SARS-CoV-2, with or without accompanying symptoms, and who have developed antiviral immunity. This allows for additional analyses of strength and durability of immunity across general populations.
Commercially available COVID-19 tests currently fall into two major categories. The first category includes molecular assays for detection of SARS-CoV-2 viral RNA using polymerase chain reaction (PCR)-based techniques or nucleic acid hybridization-related strategies. The second category includes serological and immunological assays that largely rely on detecting antibodies produced by individuals as a result of exposure to the virus or on detection of antigenic proteins in infected individuals. It is important to reemphasize that these two categories of tests serve overlapping purposes in management of the COVID-19 pandemic. Testing for SARS-CoV-2 viral RNA identifies SARS-CoV-2-infected individuals during the acute phase of infection. Serological testing subsequently identifies individuals who have developed antibodies to the virus and could be potential convalescent plasma donors. It also furthers the ability to conduct contact tracing and monitor the immune status of individuals and groups over time.3