Laboratory testing for the respiratory coronavirus disease 2019 (COVID-19) and the associated SARS-CoV-2 virus includes methods that detect the presence of virus and those that detect antibodies produced in response to infection. Detection of antibodies (serology) can be used both for clinical purposes and population surveillance.
Due to limited testing, as of March 2020 no countries had reliable data on the prevalence of the virus in their population.This variability also affects reported case-fatality rates.Using real time reverse transcription polymerase chain reaction (rRT-PCR) the test can be done on respiratory samples obtained by various methods, including nasopharyngeal swab or sputum sample. Results are generally available within a few hours to 2 days.
Molecular methods leverage polymerase chain reaction (PCR) along with nucleic acid tests, and other advanced analytical techniques, to detect the genetic material of the virus using real-time reverse transcription polymerase chain reaction for diagnostic purposes.
One of the early PCR tests was developed at Charité in Berlin in January 2020 using real-time reverse transcription polymerase chain reaction (rRT-PCR), and formed the basis of 250,000 kits for distribution by the World Health Organization (WHO).In the United States, the Centers for Disease Control and Prevention (CDC) is distributing its 2019-Novel Coronavirus (2019-nCoV) Real-Time RT-PCR Diagnostic Panel to public health labs through the International Reagent Resource.
One of three genetic tests in older versions of the test kits caused inconclusive results due to faulty reagents, and a bottleneck of testing at the CDC in Atlanta; this resulted in an average of fewer than 100 samples a day being successfully processed throughout the whole of February 2020.