![]() At-home sample-collection methods are also emerging as relatively safe options and have been validated by several countries. Such centers help reduce not only waiting times but also the risk of contagion to healthcare providers and others. To collect more samples, countries have also expanded testing sites by establishing drive- and walk-through testing centers. 4 Anne Louise Wyllie et al., “Saliva is more sensitive for SARS-CoV-2 detection in COVID-19 patients than nasopharyngeal swabs,” medRxiv, April 22, 2020,. Studies indicate that the test results from such alternatives could be as accurate as those taken from swabs. Some health authorities have approved alternative transport mediums (such as saline) and different types of samples (such as saliva and lower-respiratory-tract samples). To increase the supply of swabs, traditional manufacturers have increased capacity, new manufacturers have been approved, and some manufacturers are using 3-D printing. Progress on addressing some of these issues has been made. A shortage of the supplies needed to collect samples (such as swabs and viral-transport mediums) and a limited number of testing sites have sometimes led to long waiting times for a COVID-19 test and to key segments of the population (such as healthcare workers) going untested. Sample collection is required for all diagnostic testing. 3 Based on estimates and figures available on May 7, 2020. To put that into perspective, the current global capacity for molecular tests within laboratories is estimated to be around 14 million to 16 million tests a week, with the number of tests actually conducted being less than 10 million per week (Exhibit 1). How’s your state doing?,” NPR, May 7, 2020, npr.org. Safra Center for Ethics at Harvard University, April 20, 2020, Alsyon Hurt, Rob Stein, and Carmel Wroth, “U.S. 2 “Roadmap to pandemic resilience: Massive scale testing, tracing, and supported isolation (TTSI) as the path to pandemic resilience for a free society,” Edmond J. The estimated number needed ranges from six million tests a week (if the economy is to be partially reopened) to 20 million a day, representing 6 percent of the population each day (if it is to be fully reopened while still controlling outbreaks). 1 Brianna Abbott and Sarah Krouse, “Coronavirus testing capacity is going unused,” Wall Street Journal, April 29, 2020, wsj.com. In the United States, for example, testing capacity stands at between three and three-and-a-half million tests a week, well below even some of the most conservative estimates of the number required. Many regions around the world are experiencing a shortage of laboratory-based molecular-assay tests. POC immunoassay tests typically leverage lateral-flow devices, similar to those deployed in pregnancy testing.Īs the testing landscape evolves, we expect the prominence of immunoassay tests and POC testing to increase. Most POC molecular-assay tests need proprietary equipment and reagents. By definition, POC testing has a lower throughput. POC tests are often executed in a hospital or clinic. Laboratory-based testing typically is large scale and needs more financial and operational investments. Patient samples are collected in clinics, hospitals, and collection centers and transported to laboratories, where testing is executed and the results produced. Immunoassays that identify COVID-19 antigens have recently been introduced and promise to be cost effective and fast, but they have not proven to be a substitute for the RT-PCR method for diagnosing active infections.īoth of these technologies can be deployed in two different settings:.It also remains unknown whether, for what period of time, and at what level of concentration antibodies confer any level of immunity. “Serology testing for COVID-19 at CDC,” US Centers for Disease Control and Prevention, May 23, 2020, cdc.gov. In most cases, they cannot be used as a reliable diagnostic test to detect active COVID-19 infections. ![]() Immunoassays that identify antibodies are used mainly to detect whether a person has been infected previously.Immunoassay testing identifies both antigens and antibodies: Molecular-assay testing, such as reverse-transcription polymerase chain reaction (RT-PCR) and isothermal amplification, identifies viral nucleic acid and signal the presence of a viral infection. ![]() There are two broad testing technologies:
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