Testing

• Author: Dumbrava, Costica
• Pages: 12-15

EPRS | European Parliamentary Research Service

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ensure that treatments, vaccines and diagnostics are globally available, accessible and affordable

and called for 'the establishment of additional funding for a 'Covid-19 research and innovation (R&I)

fund' to boost its efforts to finance speedy research on a vaccine and/or treatment'.

4. Testing

Diagnostic testing is essential for identifying people infected with Covid-19 and thus is key to efforts

to contain the spread of the virus. Other types of testing, such as testing for antibodies, may be

useful for monitoring and understanding the disease. It is also suggested that antibody tests could

play a key role in easing containment measures.

4.1. Types of tests

There are two main types of tests69 used to detect the SARS-CoV-2 virus: molecular tests, which

detect the presence of viral genetic material or components of the virus in a patient sample; and

serologic (or antibody) tests, which detect the immune response to the virus (whether a person has

developed antibodies against the virus).

Molecular tests are diagnostic tests, meaning that they ascertain whether or not a person has been

infected with the virus. If applied systematically, molecular tests can help to reduce the spread of

the virus significantly. There are two main subtypes of molecular tests for identifying SARS-CoV-2:

tests that detect the virus's genetic material by a method called reverse transcription polymerase

chain reaction (RT-PCR), and tests that detect components of the virus, such as proteins on its surface

(antigen tests). The main constraints related to conventional RT-PCR molecular tests are that they

entail laborious procedures and complex logistics (lab, sampling, transport, and communication of

results) and require time, expertise and scarce supplies (swabs, reagents). For this reason, efforts

have been dedicated to finding rapid diagnostic tests that can be used outside a hospital and even

without using a lab.

Antigen diagnostic tests, which seek to detect the presence of viral proteins in samples, are faster

and easier to administer than molecular tests. In theory, a reliable antigen test could be easy to scale

up and may even be used at home.70 For example, an antigen-based test developed in Belgium ca n

reportedly71 identify an infected person within 15 minutes at point-of-care sites. The test, however,

is so far only able to detect infections in about six out of ten people. Pointing at evidence suggesting

that 'half or more of Covid-19 infected patients might be missed' by various rapid diagnostic tests,

the WHO recommended not using antigen-detecting rapid diagnostic tests for patient care.72

Whereas molecular tests look for evidence of viral genetic material, serological or antibody tests

seek to detect human antibodies that signal an immune response against the virus. Antibody tests

can be used for a number of purposes: diagnostic (identifying infected people); disease monitoring

(assessing how many people in a population have been infected) and immunity assessment (e.g.

with a view to easing restrictions).

69 OECD (Testing for COVID-19: A way to lift confinement restrictions), footnote 11 (above).

70 N. V. Patel, 'Antigen testing could be a faster, cheaper way to diagnose covid-19',

MIT Technology Review

,

24 April 2020.

71 P. Rejcek, 'New antigen test for detecting COVID-19 could help triage patients during the pandemic',

Frontiers Science

News

, 8 May 2020.

72 WHO, Advice on the use of point-of-care immunodiagnostic tests for COVID-19, Scientific Brief, 8 April 2020.