PCR | Rapid antigen test | |
---|---|---|
Price | €80 | €10 |
Difficulty | Very high | Low |
Time results | 1-3 days | 30 min |
Reliability | 5/5 | 3/5 |
Technology | Molecular biology | Colorimetry |
PCR (molecular biology)
- It allows detecting the presence of a fragment of specific genetic material, taking advantage of the chemical reactions that take place inside cells.
- Amplify the fragment of genetic material by giving a positive.
- Being positive is not being sick, the disease may not develop (asymptomatic).
Rapid antigen test (colorimetry)
The virus enters the body and generates infection, as a result, antigens are produced, which are proteins that the virus has around (spicules). The spicules act as keys to adhere and penetrate the cell, infecting it.
If the test detects proteins, a paper is stained with bands (colorimetry) and indicates that you are infected.
Asymptomatic patients do not generate infection, therefore antigens (proteins) are not produced and the paper is not stained with bands.
How is the sample taken?
In both tests, the sample is taken from the nasopharynx with a swab.

When to perform a PCR?
- Symptoms compatible with COVID-19
- Patients who have tested negative in Ag rapid test but triage shows COVID-19 symptoms
- Asymptomatic patients in the infectious contagious phase.
- Close contacts of positives.
- For epidemiological prevention.
When to perform a rapid antigen test?
- Evolution of symptoms between 1 and 5 days.
- Close contact of a confirmed positive. Between 1 and 5 days after the exhibition.