Types of Covid-19 tests

2. In PCR you repeatedly amplify the amount of potentially present viral RNA by
heating and cooling the sample until a sensor indicates if the virus is present. The
higher the initial amount of RNA, the faster the sensor picks this up. The lower
the Cycle treshold (“Ct”) value, the more infectious you are.
Most commonly nasopharyngeal samples are being used, but recent data
suggests that the combination of nasal + oropharyngeal / saliva samples also
provides good results.
RT-PCR

3. Antigens“ANTIbody GENerator” is a small particle from a virus that causes
antibodies to be formed. The test has little strips that work similarly
topregnancy tests - if in the sample (swab/saliva/blood) there is a virus
protein that can attach to an antibody – there is a color change and a little red
strip forms
ANTIGEN

4. Antibodies indicate if you have had an infection in the past, it does not tell
you if someone is infectious. For COVID-19, the most important ones are:
IgG (past infection), IgM (still infective / got infected recently), IgA
(mucosal). Most countries only accept venous blood sampling for antibody
testing – not finger prick tests, which makes it necessary to visit a test
center
ANTIBODIES

5. Loop-mediated isothermal amplification” is like PCR at one temperature (without
heating/cooling). We like it because it’s fast (results in 20-30 min), cheaper than
PCR,and has a similar sensitivity.
Why is it not being commonly used? PCR has been used since the 80s and most labs
are familiar with it. LAMP was invented in the 90s – it has not been popularized as
much because there was no need for it. With the pandemic people started looking for
new, more efficient ways to test. A year ago not a single country accepted LAMP based
certificates, and now we have over a dozen.
LAMP