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The COVID-19 test is the only reliable way to find out if a person is actually infected with the new coronavirus, as the symptoms can be very similar to those of the common flu, making diagnosis difficult.
In addition to this test, the diagnosis of COVID-19 may also include the performance of other tests, mainly blood count and chest tomography, to assess the degree of infection and identify if there is any type of complication that needs more specific treatment.
Since it is a test for a new type of virus, below we explain some of the most common questions:
1. Who should take the test?
The test for COVID-19 is not indicated in all cases, and should only be performed on people who have symptoms suggestive of the infection, such as severe cough, fever and shortness of breath, and who fall into any of the following groups:
- Patients admitted to the hospital and other health institutions;
- People over 65;
- People with chronic diseases, such as diabetes, kidney failure, hypertension or respiratory diseases;
- People undergoing treatment with drugs that lower immunity, such as immunosuppressants or corticosteroids;
- Health professionals working with COVID-19 cases.
In addition, the doctor can also order the test for COVID-19 whenever anyone has symptoms of the infection after being in a place with a high number of cases or having been in direct contact with suspected or confirmed cases.
Take our online symptom test to find out your risk of having COVID-19.
2. How is the test done?
To perform the COVID-19 test, a sample of respiratory secretions from the throat and nose region is usually collected using a swab, which is a kind of large cotton swab. This sample is then saved and sent to the laboratory, where it will be analyzed to identify whether the new coronavirus is present.
In addition to respiratory secretions, in some cases, a blood or phlegm sample may also be collected, depending on the laboratory that will perform the test.
Swab for the COVID-19 test
3. Are there any quick tests for COVID-19?
The diagnosis of COVID-19 can also be made by means of rapid tests, which provide the result in a few minutes, however, the result of these tests always needs to be confirmed with a laboratory exam.
Even so, these rapid tests can be used in the first stage of diagnosis, as they allow you to place the person in isolation until they receive the result of the laboratory test, thus reducing the risk of transmitting the virus to other people, if they are infected.
4. How long does the result take?
The time it takes the result to be released depends on the type of test that is performed, and can vary between 15 minutes to 7 days.
The fastest tests show results between 15 and 30 minutes, but your result needs to be confirmed with a laboratory test. The results of the laboratory test can take between 12 hours and 7 days.
5. Is there a chance that the result will be "false"?
Most of the tests developed for COVID-19 are very sensitive and specific, therefore there is a low probability of error in the diagnosis. However, the risk of obtaining a false result is greater when the samples are collected at very early stages of the infection, as it is more likely that the virus has not replicated enough, nor stimulated the immune system's response, to be detected.
In addition, when the sample is not collected, transported or stored correctly, it is also possible to obtain a "false negative" result. In such cases it is necessary that the test be repeated, especially if the person shows signs and symptoms of the infection, if he has had contact with suspected or confirmed cases of the disease, or if he belongs to a group at risk for COVID-19.
6. How is the laboratory test analyzed?
The laboratory test for COVID-19 is done through a process known as PCR (Polymerase Chain Reaction), which is a technique that aims to increase the number of fragments of the genetic material of small microorganisms, such as viruses, making it easier to identify whether the virus, in this case the new coronavirus, is actually present in the evaluated sample.
In addition, this test is performed in real time, which means that, in addition to identifying the presence or absence of the virus, it is also able to give information about how the virus is multiplying, providing important data on the severity of the infection.
The result of the PCR exam takes longer to be released than other types of tests, but it is considered the "gold standard" for the diagnosis of COVID-19, as it is a very sensitive and specific technique, providing important results for follow-up. disease.