WINDOW PERIOD
Is the minimum and necessary time to be able to perform a test for any sexually transmitted disease.
WHAT IS THE WINDOW PERIOD?
The window period is the minimum and necessary time to be able to perform a test for any sexually transmitted disease, this period being very different for each of them.
It is true that there are techniques, such as the test called PCR (Polymerase Chain Reaction), which even without having any symptoms, can detect any remaining bacteria in our body after only 48-72h after risk contact. But, in case of having a negative result, it can never be considered as definitive since, as established by international medical guidelines, any bacterium can appear up to the established window periods.
On the Internet there are many different sources and we even know centers that do not meet the window period established by these international guides, which, as we have seen on occasion, with a first negative result at 48h, after a second test a once the window period has been completed, a positive result can come out.
In Pyrena Medical Center we always comply with the legality of following international guidelines, for that reason, our patients always come out with the correct diagnosis, in the most effective and correct way possible.
HOW MUCH TIME SHOULD I WAIT TO MAKE ME A TEST?
The waiting times or also called “window period” for each Sexually Transmitted Disease, would be as follows:
• Gonorrhea
– 1 week
• Chlamydia
– 2 weeks
• Syphilis
– 3 weeks
• HIV
– 10 days if we look for the virus RNA (by PCR)
– 3 weeks if we look for the p24 antigen
– 3 months if we only look for Antibodies
• Hepatitis C
– 14 days for Viral Load
– 3 months by Antibody test
• Hepatitis B
– 4 weeks
Here we explain the different window periods of 
HIV and its tests:
As we can see in the graph, after a contact and possible contagion with someone with HIV, the first thing to seem logically is the virus itself, with which the techniques that should be used are those called PCR or Viral Load, which are precisely those techniques that directly look for viral RNA.
But, why do it at 10 days and not at 7 days? The main reason is that, like any existing technique in the markup, they have a limit of detection, or in other words, they detect a certain amount of virus, which means that it is risky to make such an early test. that our organism is infected, these techniques could not reach the minimum detectable limits of viral RNA. For this reason you should always leave a margin of at least 3 more days, to ensure that there is enough genetic material to be detected.
Next, after the contact of our blood with the Virus HIV, there is a test called 4th Generation, which is looking for, simultaneously, Antibodies and p24 Antigen, but what is the p24 Antigen? It is a component that is found in the viral capsid of HIV and can be detected at 3 weeks after the possible infection.
And finally, we find the conventional tests, that like any other virus, after an initial exposure, our body will start to fight the virus with Antibodies, the problem of these tests, is that, until after 3 months, the levels of Antibodies They are not high enough in our body to be detected.
