More than 20,000 tests in the Algarve made using a method that tests 10 people at once

in News · 05-07-2020 18:00:00 · 1 Comments

The Algarve Biomedical Centre (ABC) consortium has already carried out about 20,000 tests on covid-19 using the 'pool' method, which allows the detection of positive cases in groups of samples tested at once, said Nuno Marques.

The president of ABC - a consortium formed by the Hospital and University Centre of the Algarve and the University of the Algarve, primarily responsible for testing covid-19 in the region and in the Alentejo -, explained to the Lusa agency that this type of testing, which he called “sample grouping”, allows you to test 10 people at once to see if there are positives.

According to Nuno Marques, instead of doing sample by sample tests, “several samples are grouped” and the “high sensitivity of the technique” of the method allows “to still detect the existence of positive cases or inconclusive cases, in the middle of a group” , increasing testing capacity and speed.

"The big benefit is that, during the same testing time, we can do 10 times more tests than those that could be done, greatly increasing laboratory capacity and giving a faster response," he argued.

Afterwards, individual tests will only be carried out if the cluster sample proves to be positive, underlined Nuno Marques, stressing that, in case the group's result is negative, everyone will know that they are without the disease.

“Basically, instead of testing one by one, we make 'pools' - we make groups - and we are testing 10”, synthesised Nuno Marques, stressing that this testing method allows “to greatly increase the test capacity” and ABC "already has about 20,000 tests done this way".

Nuno Marques said that ABC carried out studies to understand how many samples it could test at once and found that the number of samples tested at one time could even be greater, but guaranteed that, "for the sake of complete safety", the option was for “making pools of 10 samples”.

“We have been using this type of tests for more than two months, since the beginning we realised that we were testing low-risk populations, because it only makes sense for low-risk cases, where the percentage of negatives is very high”, he explained.

According to the official, if the test proves to be positive, it will be necessary, next, “to perform the PCR again [method used for the detection of the virus] to verify which one is positive”, he justified.

The ABC president acknowledged that, if there are many positives, “it makes no sense” to “pool”, but for screening in populations “with a low number of cases expected”, this method “increases testing capacity 10 times in terms of time consumed”.

According to Nuno Marques, ABC was the entity that started doing this testing in Portugal, after a study produced in Germany with “very few patients”, and which has already been followed by other centres in the country.

“We took it [German study], developed and tested it to see how far we could go in terms of security. Up to 64 ‘pools’ it is possible to go without significantly decreasing sensitivity, but it’s starting to decrease a little. We didn't want to take any chances and, therefore, we used 'pools' of 10”, he said.

Nuno Marques was pleased that these results were already being shared with other countries so that they could be replicated in their territories.

"We had videoconferences with representatives with teams from London and the United Kingdom will adopt this type of testing with the formula we are using at ABC", he said.

On the other hand, there is also information to report that other countries, such as the United States, are also studying the possibility of using this testing method.


Português people in Portugal have so many practical habits and things that are surprisingly missing from many other countries. Saving people from extra trouble and waste of resource. In my experience it's one of the things that contribute to the relaxing charm of Portugal especially if you go there to stay more like living there for a time rather then just for a visit.

By Kari Lehto from Other on 06-07-2020 03:57
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