What are the NAAT, LAMP, and PCR tests? These are requested from travelers to enter El Salvador

The sanitary provisions have already been sent to the General Directorate of Migration and Foreigners

Among the new sanitary provisions established by the Ministry of Health for the entry of travelers to El Salvador, the request for any of these tests stands out: NAAT, LAMP and negative PCR for Covid-19.

These must be issued within a period of no more than 72 hours prior to their arrival in Salvadoran territory.

But what are the NAAT, LAMP and PCR tests, here are some characteristics of each one, according to the Centers for Disease Control and Prevention, also referred to as the CDC, of ​​the United States.

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PCR or NAAT test (Polymerase Chain Reaction, PCR, or Nucleic acid amplification test, NAAT): This type of test, also called molecular or viral, is performed by a swab in the nose or mouth.

It detects a part of the genetic material of the virus. Currently, it is considered the best test to determine if a person recently acquired the virus, but this type of test can continue to show positive results long after the person stops infecting and is not at risk of spreading the virus.


There must be enough viral load for the test to detect the virus. There is a time between when the person is exposed to the virus and when the level of viral load is detectable for the test result to be positive.

A negative test does not rule out the possibility that the person will quickly become ill from the virus. If the person is tested too soon after being exposed to the virus, they may get a negative result even if it is later determined that they were infected.

A person who was instructed to quarantine after being exposed to a positive case of COVID-19 cannot shorten the quarantine period even if they received a negative test result, as the test may have been performed. test at a time when the virus was not detectable.

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If the person has symptoms of COVID-19, this test can usually reliably detect the virus; and a negative test indicates that the symptoms are not caused by the COVID-19 virus.

A positive test does NOT necessarily indicate that the person still has the ability to spread the virus. When symptoms appear or when the test is performed is used to determine if the person can still spread the virus.

While, LAMP tests (Loop-Mediated Isothermal Amplification) are simpler and inexpensive.

They can be carried out in both decentralized facilities and laboratories, and are recommended especially when quick results are required.

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LAMP (nasal antigen) tests allow rapid diagnosis in the early stage, when there is a higher viral load, and is performed through a nose or mouth swab.

To do this, the sample is taken from the patient’s saliva. Then, it is heated to 95 ° Celsius to amplify possible traces of the virus and, thus, the result is obtained without the need for molecular biology laboratories or other specialized equipment.

The result is manifested by a color change in the sample: yellow if it is positive and red if the test is negative, depending on the pH indicator used.

Its main advantage is that the same person could collect the saliva sample without requiring highly specialized health personnel, which reduces the chances of contagion in the healthcare team and reduces costs, since no special swabs and culture media are required for transporting them.

But not only that. The LAMP test is cheaper, does not require sophisticated equipment to amplify the genetic material of the virus, and results can be obtained in approximately one hour.


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