Publication: Thursday, December 10, 2020 3:44 PM
In addition to the PCR, from this Thursday a negative result in a TMA test is also valid for entering Spain from countries considered at risk of coronavirus.
These tests, very similar to PCR, are nevertheless more affordable and faster. As with PCR or antigen testing, for TMA testing, it is necessary to insert a swab – the stick – into the nose to obtain the sample.
We review its characteristics and the differences and similarities with other types of tests:
Same reliability as PCR
Its sensitivity is the maximum available: identical to PCR and superior to that of antigenic tests. These tests show whether the person is infected even though they are asymptomatic and have a low viral load.
The reason is that it looks for the same as a PCR, genetic remains of the virus. However, the technique is simpler, but just as thorough.
“TMA produces copies of the RNA genome itself, reaching amplification levels that can be comparable, equivalent or, in some cases, even higher than those of PCR,” explains Carmen Galán, expert in molecular diagnostics.
Faster and cheaper
According to virologist Estanislao Nistal, moreover, with TMA tests “the times can be reduced and the price of the reaction can be lowered, because the necessary equipment is not as complex as that of PCR”.
The result takes about two hours, compared to 24 to 48 hours for PCR, and they are cheaper: around 100 euros compared to the 130 that are usually priced for PCR.
The problem for now is that they need a technology and a machine, offered primarily by the pharmaceutical company Grifols, which is much less widespread than that of PCR, which is why for the moment they are not available in most laboratories.