How can I recognize HIV early on

HIV & AIDS: examinations & diagnosis

The earlier an infection with the HI virus is detected, the better the internist can decide when the optimal time has come to give the patient antiviral treatment. The less advanced the AIDS disease, the better the chances of success of the treatment. People who belong to a risk group or who have been exposed to a risk situation should therefore absolutely have themselves tested to see whether they have contracted the HI virus. In addition, people can transmit the pathogen to their partners through ignorance during unprotected sexual intercourse. Knowing the HIV status therefore also protects the partner.

Overview:

  • HIV tests
  • Determination of the viral load
  • Resistance test

HIV tests

Tests for antibodies to HIV have to be very sensitive and very specific. They must not overlook any antibodies that are present, nor should they mistakenly mistake other antibodies for HIV antibodies. For an addiction test, on the other hand, it is better to go too far and show some false positive test results than not to detect infected patients. A positive result in the search test must therefore always be carried out with the help of a second test procedure, the so-called confirmation test (Western blot) should be checked. To be on the safe side, a second blood sample from the test person is generally examined.

An HIV test is usually a search for antibodies in the body against the HIV virus in the blood (ELISA test). Antibodies against the HI virus are formed within 3-12 weeks after infection. If a person is infected with HIV, antibodies can already be detected 6 weeks after the transmission in approx. 80% of the cases. After 8 weeks it is almost 95% and after 12 weeks almost everyone has developed HIV antibodies. An antibody test should therefore be carried out at the earliest 6 weeks after a possible infection.

With an ELISA test (search test), the internist can detect almost any infection. In 0.5% of the cases, however, it gives a positive result, although the test person is not infected at all (false positive result). Therefore, a positive result must be confirmed by a second test (confirmation test). In order to rule out a mix-up, this test is usually repeated from a second blood sample.

The implementation of an HIV test is subject to approval. Only the positive result of the confirmation test can be communicated to the affected person. Health authorities and many AIDS organizations offer free and anonymous HIV tests. Doctors in private practice must charge a small fee when ordering an HIV test. The HIV test by a doctor is only free of charge as part of prenatal care.

Infected despite a negative test result

A negative test result means that the test person had not developed any antibodies against the HI virus at the time of the examination. However, this does not mean that the test person is definitely not infected with HIV. The time of infection could have been so short that the body was not yet able to produce any detectable antibodies.

A positive test result means that the test person has contracted HIV. The person affected can therefore transmit the HIV virus to HIV-negative partners. However, the result does not mean that the person affected is already suffering from AIDS.

Direct detection detects viruses at an early stage

In addition, the internist can also directly detect the viruses in the blood of HIV patients (PCR). This test detects the genetic makeup of the virus just 1-2 weeks after infection. However, it is expensive and is therefore normally only used in special situations e.g. B. carried out in certain emergency situations, in acute HIV infections before possible early treatment or in newborns, as they only develop their own antibodies against the pathogen at the age of 12-15 months.

In addition, there are now rapid tests that deliver a result in less than half an hour. However, these rapid tests are not as reliable as the detection of antibodies using conventional tests. In particular, positive results of a rapid test should therefore be confirmed by a reliable antibody test.

Determination of the viral load

Two blood values ​​show the course of an HIV infection: the CD4 cell count and the viral load. The internist therefore usually checks these values ​​in HIV patients at certain intervals, e.g. B. every three months.

The CD4 cells are among the white blood cells that activate the immune system. Since they are infected and increasingly destroyed by HI viruses, their existence in the blood allows conclusions to be drawn about the extent of the damage to the immune system. In a healthy, HIV-negative adult, CD4 counts are usually over 800 per microliter of blood. If an HIV patient's CD4 cell count falls below 200 per microliter of blood, his immune system is no longer strong enough to prevent other infections. This is the time when the attending physician will begin treatment with medication regardless of the presence of symptoms or HIV-specific diseases.

Based on the CD4 cell count, HIV patients are divided into 3 different stages of the disease:

Patients of the Category A are infected with the HI virus, but show no symptoms of the disease. In the Category B. the patients suffer from diseases that are not AIDS-defining, but are related to the immune deficiency. Category C patients show the so-called AIDS-defining diseases (opportunistic diseases) that do not occur in a healthy immune system.

The viral load indicates the number of HIV viruses per milliliter of blood. The aim of drug treatment is to reduce the number of virus particles below the detection limit, which is currently 50 copies per milliliter of blood. This allows the number of CD4 cells to recover over the following years.

However, the HI viruses are not only found in the blood. They also travel to the intestines, brain, lymph nodes, and testicles. The drugs are often unable to destroy the pathogens in these tissues. It is therefore possible that HIV patients infect their partners even though their viral load in the blood is below the detection limit. A detection of the viral load outside of the blood is not part of the routine examinations.

Resistance test

There are many variants of the HI virus, as the pathogen is a very changeable virus. HIV adapts very quickly to its environment and, as it reproduces, forms offspring with slightly altered genetic material (RNA). These changes in the RNA are called mutations. Some of these variants can now succeed in bypassing the defense mechanisms of the immune system or the points of attack of antiviral drugs. The drugs then lose their effect and the further developed variant of the pathogen multiplies unhindered - one then speaks of one resistance.

In some cases, those affected become infected with such resistant (mutated) viruses. That is why experts often recommend a resistance test before drug treatment. This test examines whether a patient has become infected with resistant HI viruses and which drugs can attack the pathogen. The internist can treat the patient with the optimal medication right from the start. Its aim is to stop the virus from multiplying as quickly as possible. Resistance can also develop over the course of treatment. The drugs then become ineffective and the viral load suddenly increases. Before the internist switches the treatment to other medication, he will also carry out a resistance test.