The emergence of the pandemic caused by Covid-19 brought with it new needs and routines. The so-called new normal, which is very little normal, consists of a set of rules of hygiene, respiratory etiquette and social distance, which we all had to get used to. The adaptation has been going on for about 8 months, and in a short time, thanks to the resilience of researchers and doctors who do everything to decode the behaviour of Sars-Cov-2, we know more than in March.
Life goes on is the premise at the Faculty of Medicine of the University of Lisbon. In order for academic life to suffer the least number of constraints and students to continue to obtain the best training, FMUL services, in line with the Research Laboratories and other units and people of our medical school have carried out, with great effort and dedication, comprehensive testing initiatives across the community.
The “new normal” led us, therefore, to better understand the rapid test procedure (PCR), already implemented at FMUL, by the team of Professor Thomas Hanscheid, from the Microbiology Institute of our Faculty, who has had the strong support of Dr Ana Catarina Pronto Laborinho, Health, Clinical Tests and Public Health Senior Technician, holder of a Ph.D. in Biomedical Sciences - Physiology Branch.
The procedure is simple: anyone in our community who thinks may be infected, or who is aware of having been in contact with an infected person, can send an email to: covid19@medicina.ulisboa.pt and, after analysis by the specialists, an appointment will be made with the date for the test, which allows results to be obtained in a short period of time, 15 minutes. After collection and analysis, the results (with about 90% specificity), will be communicated by the team of the Institute of Microbiology.
Doctor Ana Catarina Pronto-Laborinho, who has been at the Faculty since 2004, gave us this short interview, explaining all the details about the advantage of the rapid tests.
Before dedicating ourselves to the reason that brought us here, who is Ana Catarina Laborinho? How long have you been at the Faculty?
Ana Catarina Laborinho (ACL): My journey at the Faculty is already long. I joined the Faculty of Medicine of the University of Lisbon in 2004, having at that stage the honour of working with Professor José Melo Cristino, with whom I learned a lot and acquired a taste for research. I have been a member of the Physiology Institute since 2011, headed by Professor Mamede de Carvalho, who besides being my “boss” (laughter), was also my supervisor. An extraordinary person, with whom I have learned a lot and who challenged me, in 2015, to do a Ph.D. in Physiology, more specifically on Amyotrophic Lateral Sclerosis. I think it is worth detailing a little. This is a neurodegenerative, progressive and fatal disease. To date, there is no drug capable of stopping the progression of the disease. On average, patients survive 3-5 years and the main cause of death is respiratory dysfunction. My personal characteristic was to look for biomarkers that can help in the diagnosis and progression of the disease. I had the opportunity to work with a multidisciplinary team from our Institute, with Professor Filomena Carvalho (Co-Supervisor) and with Professor Nuno Santos, from the Biochemistry Institute. With their help, it was possible to use very innovative techniques, such as atomic force microscopy, with very interesting results, which will be published soon.
Regarding this new normal, which makes it necessary to test all those who show the possibility of having Covid-19 infection, how did you get here? Did you volunteer?
ACL: In fact, it was Dr Isabel Aguiar who invited me to join the testing team and obviously I found the challenge very interesting. As I love new challenges, I accepted immediately. Above all, because it is part of my training area: Clinical Tests and Public Health.
How are people selected? What are the criteria for coming here to have the tests?
ACL: The validation of the appointments is not done by me. An initial assessment of each individual situation is carried out by doctors and specialized professionals, and according to the individual assessment, they are sent here. We are available to test all people at the Faculty who are aware of having been in contact with infected people. But, mainly students, because they do internships in hospitals, and for safety reasons, they need to know whether or not they are positive for SARS-CoV-2. The Faculty is always very committed to providing the greatest security to students and our community, right from the beginning of the pandemic.
On average, how many tests do you perform per day?
ACL: We are still at a very early stage, adjusting our capabilities, because we have to reconcile the tests with our other professional activities. On the part of the Faculty, there is me and my colleague Adriana Justo, also in clinical analysis, and then there is a whole back office support team, Dr Isabel Aguiar and Gabriela Fernandes. The coordinating team is composed of Professor Emília Valadas and Professor Thomas Hanscheid, clinical pathologist, who should be here soon. On average, we have had 12 to 13 people per day, but this number has been increasing.
Q: Would it be possible to describe the care and procedures for carrying out the tests?
ACL: Antigen tests, developed for the diagnosis of SARS-CoV-2, aim to detect virus-specific proteins produced in the respiratory tract. They are performed by taking samples of exudate, usually from the nasopharynx that is obtained from a swab. The technology involved is similar to a pregnancy test and the screening of each situation is an essential factor (carried out by the persons that make up the working group).
Each member of the academic community must be tested within the period indicated for this test. It should be performed by professionals qualified for this purpose, who have higher and validated education to carry out collections, since if the sample collection procedure is not performed correctly, we may face false results. Hence the need to have Diagnostic and Therapeutic, Clinical Tests and Public Health Senior Technicians carrying out this type of testing.
In addition, the test must be carried out according to the manufacturer's recommendations, and the test we have done is Abbot's rapid antigen test, consisting of a simple and very practical procedure to be performed by qualified professionals. After collecting the sample, using a nasopharyngeal swab, it is placed in a specific buffer solution, and we have a result in 15 minutes. Subsequently, negative and positive controls must be carried out to validate our work. Then, all results are analyzed by the Clinical Pathologist, Professor Thomas Hanscheid, who validates them so that they can be released.
Are you afraid to be here and contact potential infected people?
ACL: If it were a few months ago, I would be much more afraid, because I knew very little, but not now!
There is always some fear, because it is a disease about which there is still much to discover, and the effects in the medium and long term are not known. At this moment, I'm not afraid, there is always fear, but we are very well protected by personal protective equipment (PPE), so the risk is reduced. On the other hand, as a health professional, I have to be where I should be to fulfil my duties, and at this point it would not make sense if I was not be doing my part. Here is Professor Thomas!
What is the procedure when you identify a positive test?
ACL: We work in a multidisciplinary team. Therefore, me and my colleague Adriana Justo, ACSP Senior Technicians from FMUL, and other colleagues from the same training area, carry out the entire procedure since the sample collection and testing, the results being directly communicated to Professor Thomas Hanscheid, who, in turn, as a clinical pathologist, validates them. The results are then released to each person who has been tested. Later, the results are analysed and each case is checked individually by the FMUL team of experts.
A few days ago, Dr Graça Freitas, during the DGS conference, said that it would be consistent to carry out the Covid-19 screening tests only when there was a medical order for this. On the other hand, we all remember a WHO advice, right from the start, which was “test, test, test”. In your opinion, which one is right?
ACL: In my opinion, the answer must be appropriate to the reality of each situation. In fact, testing is important and fundamental, but within the specific guidelines of the responsible entities. The WHO and the DGS do not recommend testing people just because they want to. Diagnostic tests for Covid-19 should be carried out after medical advice and by qualified health professionals who have a duty to record the results, so that health authorities can maintain the epidemiological surveillance of the disease in Portugal.
In fact, I am an advocate of testing, but within a framework of norms defined by the right entities. The attending physician and the DGS act according to the analysis and consideration of the clinical and epidemiological situation evidenced by each individual. I do not think it is pertinent to have a test when I pass someone who is coughing and I fear that I may be infected. There are predefined criteria and it is up to the doctor or health delegate to decide the need for the test. In the present case, the rapid tests must be carried out within a certain time window and on medical recommendation.
Otherwise, in certain situations when the appropriate criteria are not met, due to lack of symptoms or lack of sensitivity and specificity of the test, there is a very high risk of having false negatives and, consequently, a certainty that a negative result may result in some negligence in the rules and regulations that must be complied with. It is an individual and collective responsibility and a duty of citizenship to protect ourselves and others. And the rules and recommendations must be adhered to, we must also think of others, because a slip of ours can endanger the lives of others. And if each of us does our part, the damage to health and society, in economic and social terms, will be much less.
You mentioned earlier that the accuracy of rapid tests is between 93 and 97%, do you confirm?
Thomas Hanscheid: Catarina, allow me to answer this question. What matters here is to assess sensitivity and specificity. I don't like the term accuracy. What exists, within the scope of these tests, are sensitivity and specificity. These terms refer to false negatives (sensitivity) and false positives (specificity). The specificity is 99% and this means that when the result is positive, in principle it is correct. Even so, 1 in 100 could be a false positive and because of that, for example for a clinical diagnosis, it may be prudent to confirm the positives by more reliable methods such as PCR.
Sensitivity is related to false negatives, which is, in a way, much more relevant. These tests seem to have a sensitivity of 80% to 90%, that is, in 100% of infected people, they do not detect about 10-20 people (false negatives). In these people, the (false) negative result can induce a false sense of security: “I have a negative test, so I am not infectious (and eventually I don't have to work so hard with the protection measures)”. This is obviously a big reasoning error and everyone must continue the protective measures!
Why do these false negative happen?
Thomas Handscheid: Why do these false negative happen? One reason has to do with the collection, for example. If the collection goes less well, the sample will be of lower quality, it is more likely to give a wrong result. But the main reason is that these rapid tests are positive when there is a high amount of virus in the airways. This usually equates to a greater risk of being infectious, and so some say that tests detect well (or better) those who are (most) infectious. Individuals who have less virus (and who are less infectious) are those in which the test is most likely to give a wrong result (false negative). So the main reason for using these tests is to identify the (most) infectious ones and remove them from circulation.
Professor, what about the mass testing that the Republic of Slovakia carried out? What's your opinion?
Thomas Hanscheid: What happened in the Republic of Slovakia can also be considered a great waste. Why? Because, with all this enormous effort, they detected, and very well, 30 thousand positive cases in people who were removed from circulation and placed in isolation. But what about those 10% false negative, not detected in the test? If I have 30,000 who are positive, it means that I may have 3,000 infected, 3,000 people with a false negative test, who circulate with false security. Even if these people belong to the group of the least infectious, they can feed the contagion chain, especially if they feel more comfortable, let their guard down and do not behave correctly, following the rules for using the mask, hand hygiene and social distancing. So, we have two situations and for me, it is very difficult to say which situation is better. Is it better to have 33 thousand infected without knowing that they are, but who behave carefully and avoid the chain of infection (and invest this enormous effort in other areas)? Or to have 30,000 identified and confined, knowing that the 10% margin of error can eventually start spreading the virus more easily? At first glance, I have an inclination towards the first scenario, that is, I would prefer to have people adopt the measures scrupulously, everyone thinking that they could be infected, which I think is less dangerous than having 3,000 false negatives, infected and circulating without care. Especially if we consider the enormous effort that this means, it is like a photograph – there is only that moment. Two/three weeks later it might be necessary to repeat everything.
Isabel Varela
Editorial Team
