With the seventh coronavirus wave in full swing and the number of positives steadily increasing, it is important that you note that a negative self-diagnostic antigen detection test result does not necessarily mean that the person has covid-19. The test's sensitivity will determine the results, according to the Spanish Agency for Medicines and Health Products. The conclusion of this type test does not confirm the diagnosis, but the individuals who have it are considered to be suspected cases. If you experience symptoms, it is best to have a second negative test performed a few days later. When should you do it?
AEMPS's covid-19 detection test explanatory notes emphasize that antigen self-diagnosis testing addresses this issue in detail due to the risks it presents. If the examination reveals a positive result, the AEMPS emphasizes that the individual who has undergone the test must immediately contact their health center to begin confinement. He says that the opposite situation does not rule out infection.
It could be that the viral load has been too low to detect. It is important to not reduce protection measures such as hand hygiene, masks, and use of a mask. The AEMPS explains that if you have covid-19 symptoms or are close to someone with the disease, you should immediately begin self-isolation and contact your local health services. This qualification is made before any infection is suspected. However, the test is positive. The antigen test is less sensitive than the PCR. False negative results can be possible if there is a low viral load, which is usually found in the final or initial days of infection.
The best way to be sure is to do the test again on subsequent days, as long as symptoms persist. If we are regularly performing tests, the diagnostic test will reflect the presence of a high viral load. Your positive test result will be confirmed within three days.
The entity clarifies, in this way, the implications of the lower sensitivity for diagnostic antigen tests that can be used in professional health centers. This type of test is more accurate than self diagnosis tests that can be bought at pharmacies and detects active infection. He says, "That's to say, with a high likelihood, there is an ongoing infected, even if there aren't any symptoms." On the other hand, the negative indicates that there is no current infection, even though it is "highly probable".
The AEMPS warns that false positives can be possible. They can be caused by contamination of the sample, or substances in it that are harmful. He also mentions that they are common in mass screening in low prevalence populations. These professional tests can also give false negatives "when there is a very low viral load or more than seven days since the beginning of the infection", and in the case that the sample was taken "inappropriately"..
It is acceptable as long as the manufacturer's instructions are followed. He determines that if it is higher than the manufacturer's instructions, then the test is not functioning correctly. To confirm a case, he states that "it is necessary for a PCR test to be performed." You should refer to the instructions for use to determine the test's reliability. These values will make the tests more reliable. The European Union recommends tests with minimum specificity of 97%, and minimum sensitivity of 90%".