The condom is the only effective prevention method against HIV, and against most other sexually transmitted infections. It is therefore important to require the wearing of a condom with each intercourse, and with each new partner, until everyone is convinced that they are HIV negative. By sexual intercourse we mean vaginal or anal penetration, but also fellatio. A broken condom during intercourse is a risky situation. For the choice of condom, do not hesitate to ask your pharmacist for advice.
HIV Testing: When to Get Tested
There is no right time to get tested. You should know that it is an act reimbursed at 100% when it is prescribed by a doctor and carried out in a medical analysis laboratory, and free and anonymous in screening centers. However, it is important to know your status after having been in a risk situation, or before stopping the condom with a stable partner. Note that HIV is not detectable until about three weeks after infection. Getting screened a few days after a risky situation is therefore of no interest: you have to wait a bit. But canada home testing is important.
What Are The Principles Of The Different Screening Tests Available?
There are two tests that are used in a complementary way in screening for HIV. Both are based on the same principle: they are immunological tests. When a foreign substance called an antigen is introduced into the human body, it reacts by producing antibodies against the foreign antigens. This is the immunological reaction. The presence of the antibodies makes it possible both to participate in the destruction of the antigens, but also, and this are what interest us here, to detect the presence of said antigen.
In summary:
- Absence of anti HIV antibodies means no HIV, i.e. seronegativity
- Presence of anti-HIV antibodies means HIV, that is to say seropositivity.
The ELISA test
This is the test used in first intention, during screening tests in centers for example. Its principle of operation is quite simple. We put in the small wells of a grid “pieces” of HIV, antigens. When you put a patient’s serum in the wells, if it contains anti-HIV antibodies, which means if the patient has HIV, these antibodies will bind to the antigen. Another antibody is then added, directed against the patient’s antibody. An enzyme capable of coloring a specific product which is originally colorless has been attached to it beforehand. Thus, if there has been fixation of antibodies from the patient’s serum, the enzyme can be fixed and therefore activated and will stain the well in pink. If there are no antibodies in the patient’s serum, the well will remain colorless.
Western Blot Test
It is a much longer, complex and expensive test, used as a second-line confirmation of a positive ELISA, or to confirm or deny a doubtful result. This method is more specific and more reliable than ELISA because it uses several different antigens, that is to say several “pieces” of different viruses. Thus, various proteins constituting the envelope of the virus and proteins found inside the virus are tested. Once the proteins are fixed on a membrane in order of size so that we can recognize them, we put them in contact with the patient’s serum. There is then fixation and staining, or not. For the test to be confirmed as positive, at least one stain is required for all envelope antigens, and at least one internal antigen.