We continue talking about diagnostic tests to learn about all the differences and similarities between them and how COVID tests are performed.
How they take the sample
In both tests discussed, the most appropriate way to take the sample is through nasopharyngeal swab. This is done by inserting a swab or cotton swab into the nose.
The other type of sample can be oropharyngeal, that is, the swab is introduced into the mouth and a saliva sample is taken. This procedure, which is simpler to perform, is pending validation since it loses sensitivity compared to the nasopharyngeal sample.
Who should take the test?
In all cases (PCR or rapid test), the sample must be taken by a trained health expert, since a poorly performed test can give a false result.
You can read more about PCR here.
Why choose one or the other?
This choice will depend on the center where we perform the test, the disposition they have and also on the symptoms or characteristics that the person presents, as well as the phase of the disease in which the person who is going to undergo the test is.
Which is more reliable?
The reliability of this type of tests is measured based on the specificity and sensitivityBut what do these terms mean?
A test will have high specificity when it is able to differentiate between two microorganisms that are very similar in evolutionary terms.
On the other hand, it will have high sensitivity if it can detect small amounts of genetic material from the virus.
If you want more information about how COVID tests are performed and other topics related to COVID-19, we invite you to join our Community insp@ir Re-COVID where you can share experiences and ask questions to our healthcare professionals.
Author:
Teresa García Barredo, Respiratory Physiotherapist at the Lovexair Foundation and HappyAir Coach.
Reviewers:
Eva Maroto López, Respiratory Physiotherapist at the Lovexair Foundation and HappyAir Coach.
Lila Martínez Ucha, Communications Department of the Lovexair Foundation.
Bibliographyed
Covid-19 Early Detection, Surveillance and Control Strategy
How PCR and rapid coronavirus tests work and how they differ
Coronavirus test, differences between rapid tests in Spain
SEIMC positioning on COVID19 microbiological diagnosis
Last updated on 7 March, 2026
