Molecular detection of the new SARS-CoV-2 coronavirus is used to confirm the infection from the virus, to monitor carriers of the disease, and for epidemiological reasons.
Molecular testing for SARS-CoV-2 coronavirus is performed by the real-time reverse polymerase chain reaction (rRT-PCR) method and is used to qualitatively detect SARS-CoV-2 coronavirus RNA from samples taken from the upper and lower respiratory tract.
Molecular testing for the coronavirus is so far the only way to diagnose COVID-19.
Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is a positive, single-stranded RNA virus that causes COVID-19. Like other coronaviruses that infect humans, SARS-CoV-2 can cause infection in both the upper and lower respiratory system. Symptoms range from mild (such as the common cold) to severe (such as pneumonia) in both healthy and immunocompromised patients. Transmission of the SARS-CoV-2 coronavirus occurs mainly through respiratory droplets. During the early stages of COVID-19, the symptoms may be nonspecific and look like other common airway infections, such as the flu.
SARS-CoV-2 coronavirus RNA is generally detectable in respiratory specimens during the acute phase of infection.
SARS-CoV-2 coronavirus is found in higher concentrations in the nasopharynx during the first 3 to 5 days of symptomatic disease. As the disease progresses, viral load tends to decrease in the upper respiratory tract, so samples from the lower respiratory tract (e.g., sputum, tracheal aspiration, bronchoalveolar lavage) are more likely to have detectable levels of SARS-CoV-2.
A positive result is evidence of the presence of SARS-CoV-2 coronavirus RNA. Correlation with the patient's history, clinical examination, and other diagnostic information are necessary to determine the clinical severity of the infection. A positive result does not rule out the presence of a bacterial infection or the concomitant infection with other viruses.
A negative result does not rule out SARS-CoV-2 coronavirus infection and should not be used as the sole basis for patient management decisions. Negative results should be combined with clinical observations, patient history, and other epidemiological information.
The molecular test to detect the new coronavirus is performed with reagents suitable for diagnostic use (CE-IVD). The minimum amount needed to detect coronaviruses is 10 viral RNA copies per sample. The test involves the detection of 3 unique genetic sites on the SARS-CoV-2 coronavirus genome, the E gene, the N gene, and the RdRp gene. Both the diagnostic specificity and the diagnostic sensitivity are 100%, according to the manufacturer of the reagents.
The results are available within the same day.
Last Updated: 05/08/2021