COVID-19 testing
Testing for the respiratory illness COVID-19 and the associated SARS-CoV-2 virus can be done by polymerase chain reaction (PCR) testing, nucleic acid tests and ELISA antibody test kits. One study published in February 2020 claims that chest CT scans perform better than PCR tests.
PCR
One of the early PCR tests was developed at Charité in Berlin in January 2020 using real-time polymerase chain reaction (RT-PCR) and formed the basis of 250,000 kits that the WHO is distributing.[1]
A South Korean company called Kogenebiotech[2] developed a clinical grade, PCR-based 2019-nCov detection kit called PowerChek Coronavirus on Jan. 28, 2020.[citation needed] It looks for the "E" gene shared by all beta coronaviruses, and the RdRp gene specific to SARS-CoV-2.[3] Other companies like Seegene and Solgent also developed their versions of clinical grade detection kits called DiaPlexQ and Allplex 2019-nCoV Assay respectively in Feb of 2020.
In the United States, the US Centers for Disease Control is distributing the CDC 2019-Novel Coronavirus (2019-nCoV) Real-Time RT-PCR Diagnostic Panel to public health labs through its International Reagent Resource.[4] One of three genetic tests in older versions of the test kits caused inconclusive results, and a bottleneck of testing at the CDC in Atlanta; tests using two components were determined to be reliable on February 28, 2020, allowing state and local laboratories to complete testing quickly.[5] The test was approved by the Food and Drug Administration under an Emergency Use Authorization.
As of 24th Jan 2020, the WHO listed the following development laboratories and protocols [6]:
| Country | Institute | Gene targets |
|---|---|---|
| China | China CDC | ORF1ab and Nucleoprotein (N) |
| Germany | Charité | RdRP, E, N |
| Hong Kong | HKU | ORF1b-nsp14, N |
| Japan | National Institute of Infectious Diseases | Spike protein (Peplomer) |
| Thailand | National Institute of Health | N |
| US | US CDC | Three targets in N gene |
Antibody
COVID-19 testing can also be done with antibody test kits. Antibody assays use a blood serum sample and can provide a positive result even if the person has recovered and the virus is no longer present. The first antibody test was demonstrated by a team at the Wuhan Institute of Virology on 17 February 2020.[7][8]
On 25 February, a team from Duke–NUS Medical School in Singapore announced another antibody test for COVID-19 that can provide a result within a few days.[8][9]
On Feb. 28th of 2020, another South Korean company called PCL filed a Fast Track Designation Request to Ministry of Food and Drug Safety of South Korea for their antibody-based detection kit, COVID-19 Ag GICA Rapid. Unlike a real-time RT-PCR based detection kit, PCL claims that their antibody-based kit could make a diagnosis within 10 min.
Nucleic acid
The 'Explify Respiratory' test by IDbyDNA is a metagenomic nucleic acid analysis test that can identify over 900 respiratory pathogens, including the SARS-CoV-2 virus strain. The actual data analysis takes less than an hour; the turnaround time from receipt of sample to test result is 36 hours. It is more expensive than PCR testing. [1]
Test kit production
China has announced it is making 1.7 million nucleic acid-based tests and 350,000 antibody test kits each day as of 25 February 2020.[10]
Sample collection
Using real time reverse transcription polymerase chain reaction (rRT-PCR)[11] the test can be done on respiratory samples obtained by various methods, including nasopharyngeal swab or sputum sample.[12] Results are generally available within a few hours to 2 days.[13]
Hong Kong has set up a scheme where suspected patients can stay home, "emergency department will give a specimen tube to the patient", they spit into it, send it back and get a test result a while after.[14]
The British NHS has announced that it will start testing suspected cases at home which saves the risk of infecting others if they come to a hospital and having to disinfect the ambulance if one is used.[15]
Chest CT scan
Chest CT scan, a routine imaging tool for pneumonia diagnosis, is fast and relatively easy to perform. One research found that the sensitivity of CT for COVID-19 infection was 98% compared to RT-PCR sensitivity of 71%. [16] For this study, researchers at Tongji Hospital in Wuhan, China, set out to investigate the diagnostic value and consistency of chest CT imaging in comparison to RT-PCR assay in COVID-19.
References
- ^ a b Sheridan, Cormac (19 February 2020). "Coronavirus and the race to distribute reliable diagnostics". Nature Biotechnology. doi:10.1038/d41587-020-00002-2.
- ^ [http://www.kogene.co.kr/eng/index.php Kogenebiotech homepage
- ^ NEW PRODUCT / COVID-19 KIT
- ^ International Reagent Resource
- ^ Transcript for the CDC Telebriefing Update on COVID-19, 28 Feb 2020
- ^ Coronavirus disease (COVID-19) technical guidance: Laboratory testing for 2019-nCoV in humans
- ^ Zhang, Wei; Du, Rong-Hui; Li, Bei; Zheng, Xiao-Shuang; Yang, Xing-Lou; Hu, Ben; Wang, Yan-Yi; Xiao, Geng-Fu; Yan, Bing; Shi, Zheng-Li; Zhou, Peng (2020-01-01). "Molecular and serological investigation of 2019-nCoV infected patients: implication of multiple shedding routes". Emerging Microbes & Infections. 9 (1): 386–389. doi:10.1080/22221751.2020.1729071. PMID 32065057.
- ^ a b NormileFeb. 27, Dennis; 2020; Pm, 4:30 (2020-02-27). "Singapore claims first use of antibody test to track coronavirus infections". Science | AAAS. Retrieved 2020-03-02.
{{cite web}}:|last2=has numeric name (help)CS1 maint: numeric names: authors list (link) - ^ "Duke-NUS used COVID-19 antibody tests to establish link between church clusters in a world-first". CNA. Retrieved 2020-03-02.
- ^ "China Makes Over 1.7 Million Covid-19 Testing Kits per Day, Official Says". Yicai Global.
- ^ "2019 Novel Coronavirus (2019-nCoV) Situation Summary". Centers for Disease Control and Prevention. 30 January 2020. Archived from the original on 26 January 2020. Retrieved 30 January 2020.
- ^ "Real-Time RT-PCR Panel for Detection 2019-nCoV". Centers for Disease Control and Prevention. 29 January 2020. Archived from the original on 30 January 2020. Retrieved 1 February 2020.
- ^ "Curetis Group Company Ares Genetics and BGI Group Collaborate to Offer Next-Generation Sequencing and PCR-based Coronavirus (2019-nCoV) Testing in Europe". GlobeNewswire News Room. 30 January 2020. Archived from the original on 31 January 2020. Retrieved 1 February 2020.
- ^ "In Age of COVID-19, Hong Kong Innovates To Test And Quarantine Thousands". NPR.org.
- ^ "NHS pilots home testing for coronavirus". MobiHealthNews. 24 February 2020.
- ^ CT provides best diagnosis for COVID-19