HIV test: Diagnosis of HIV / AIDS infection

human immunodeficiency (Human Immunodeficiency Virus, HIV) in serum, saliva or urine. These tests can detect antibodies, antigens or RNA: depending on the analyte, there are, in fact, various types of tests used for the diagnosis of HIV / AIDS. The "traditional" one is an ELISA test (Enzyme-Linked Immunosorbent Assay), a test capable of detecting the presence of anti-HIV antibodies in the blood, processed by the body when it comes into contact with the virus that causes AIDS.

AIDS is caused by HIV

AIDS is a disease caused by HIV infection, a virus that attacks the human immune system, causing a progressive reduction of the body's defenses until it cancels its response against other infectious agents and some neoplastic processes (such as lymphomas, favored by a very serious immune compromise).
The acquired immunodeficiency syndrome, tumors and opportunistic infections related to it are, therefore, the direct or indirect consequence of an "infection with HIV-1 and HIV-2.
The immune alteration typical of AIDS is largely due to the selective deficiency of a subpopulation of cells essential to the immune response, called CD4 + T lymphocytes, which are infected by the virus.
A person infected with the virus is called HIV positive.
The virus and the disease are often referred to together as HIV / AIDS.

For further information: AIDS - HIV infection (HIV / AIDS) to permanently eliminate HIV from the body. However, timely diagnosis and treatment can greatly delay or even prevent the onset of AIDS.

to that of the appearance of specific antibodies) from the last risk behavior (for example, sexual intercourse not protected by a condom).

If confirmed, the presence of antibodies against HIV is not an indication of disease (AIDS), but only that the infection has occurred. The positive test is then confirmed with second level tests, such as a Western Blot, which definitively confirms that it is infection occurred.

COMBINED TEST (antibody + antigenic): search for specific antibodies and viral antigens in the blood

Combined tests - also known as IV generation HIV tests - look for antibodies to HIV produced by the individual and parts of the virus, such as the p24 antigen (protein present in the core of the HIV-1 virus, i.e. in its internal part).

that provide a result in minutes. They can be done on a drop of blood (taken with a lancing device) or on saliva.

In case of doubtful or reactive (positive) results in rapid HIV tests, confirmation with venous sampling is required.

HIV: Quick Saliva Test

For some years now, a rapid response test has been available which allows to detect the possible presence of anti-HIV antibodies in saliva (gingival exudate).

The examination is based on an immunochromatographic technique and allows results to be obtained in 15-20 minutes. The test is carried out by sliding a sterile and disposable swab along the upper and lower gingival arches, then immersed in a solution that allows the migration of the sample along the solid support, where there is a "reaction area. If present in saliva, the anti-HIV IgG and IgM antibodies will form a complex with the viral antigens (peptides of the protein Envelope); the reaction occurred is indicated by the appearance of a red band in the device.

The saliva test is qualitative, therefore it has a lower sensitivity than HIV tests performed on blood samples and can give rise to false negatives. Its reliability can be influenced by having drunk or eaten in the last 15 minutes or in the if oral hygiene products have been used 30 minutes before execution.

Therefore, if it is doubtful or reactive, it will be necessary to ascertain the HIV infection with ELISA and Western Blot methods on venous sampling. The quick test on saliva is still valid to allow the carrying out of the HIV test during educational-information campaigns. .

, anal) not protected by condom with partners whose serological status is unknown;

If you have a stable relationship and want to give up the use of condoms;

In case of sexual assault with penetration;

Before or immediately at the beginning of a pregnancy;

In the presence of other sexually transmitted infections;

If you have used syringes or tools for the use of psychoactive substances that have already been used by others.

After How long to take the HIV test from the presumed contagion?

HIV testing should not be performed immediately following the risky behavior or situation. When the virus enters the body, anti-HIV antibodies are not formed immediately and the infection cannot be detected. There is, in fact, the so-called "window period" during which one has been infected and contagious, but seroconversion has not yet occurred, that is, you have not yet become seropositive.In other words, specific antibodies to HIV have not yet formed and the ELISA test is negative even though you have been infected.

HIV Test Window Period: How Long Does It Last?

HIV tests provide a certain result after times other than the last risk behavior (window period). In order for the test result to be considered definitive, the maximum possible length of the window period must be taken into account.

Combined tests (anti-HIV antibodies + viral antigens) can highlight the infection already after 20-22 days. The window period is 40 days from the last risk behavior.
Tests that look for only anti-HIV antibodies (such as those of the III generation) can show that the infection has taken place as early as 3-4 weeks. The window period is 90 days.

, toxoplasmosis, etc.) as occurs in AIDS. Although being seropositive, it is possible to live for years without any symptoms and notice the infection. In this period, moreover, it is possible to resort to antiretroviral drugs (HAART therapy) which reduce and block the viral replication, improving the quality of life and prolonging the survival of HIV-positive people. AIDS occurs when the immune defenses have been damaged and are no longer able to protect the organism from normally harmless microorganisms, putting the patient in serious danger of life .