The mention of “HIV” on analysis reports can raise questions. Medical terms sometimes seem complex. This article aims to clarify what HIV screening entails. It will provide the necessary information to understand your results and approach the future with peace of mind.

What is HIV?

Human Immunodeficiency Virus (HIV) is not a classic blood marker. It is a virus that can be detected in the blood. Screening therefore does not measure a natural substance in the body. Instead, it looks for specific antibodies produced in response to the virus or direct components of the virus itself.

How the virus works

HIV primarily targets CD4+ T lymphocytes. These are white blood cells that play a central role in our immune system. Indeed, these cells organize the body’s defense against infections. The virus attaches to them, penetrates inside, and uses their own machinery to multiply.

One can imagine the immune system as an army. CD4+ T lymphocytes would be the generals. HIV then acts like a spy who neutralizes the command. This progressively paralyzes all defenses. This strategy allows the virus to weaken the entire protective system of the body.

Why test for HIV in the blood?

Measuring HIV in the blood is essential for diagnosing an infection. Serological tests detect antibodies that the body produces to defend itself. Other tests, such as PCR, directly search for the virus’s genetic material. These methods allow for early identification of the infection. Consequently, rapid and effective management becomes possible.

Why is it important to understand an HIV infection?

HIV is a virus whose implications can affect the entire body. This viral infection primarily influences the immune system. The virus progressively weakens CD4+ T lymphocytes. It then makes the organism more vulnerable to opportunistic infections. These would not develop in a person with a healthy immune system.

Our knowledge of HIV has evolved significantly since its discovery. Once considered fatal, the infection is now a manageable chronic condition. According to WHO, nearly 39.9 million people live with HIV worldwide (2023 figures). Furthermore, current treatments allow for a near-normal life expectancy if diagnosed early.

Undetected HIV infection can have serious consequences. Without treatment, the virus continues to multiply and destroy CD4+ T lymphocytes. This silent degradation can last several years. When the immune system is severely weakened, the person reaches the AIDS (Acquired Immunodeficiency Syndrome) stage. This stage is characterized by potentially serious illnesses.

How to read and understand your HIV screening results

When you receive an HIV screening result, several pieces of information are important. Here is a typical example of a result:

• HIV test (anti-HIV 1 and 2 antibodies + p24 Ag): NEGATIVE
• Method: 4th generation ELISA
• Threshold value: < 1 (index)
• Your result: 0.3 (index)

The main result (“NEGATIVE”) is always highlighted. The abbreviation “Ac” stands for antibodies. “Ag p24” refers to the p24 antigen, a viral protein detectable early. “ELISA” is the technique used.

Laboratories define reference values. For HIV screening, the concept of a threshold is crucial. Below a certain value (here, 1), the test is negative. Above it, it is positive or indeterminate. A confirmation test is then necessary.

Mini-checklist for interpreting your results

• Identify the conclusion (positive/negative/indeterminate).
• Verify that the test detects both types of HIV (1 and 2).
• Note the method used (4th generation is very sensitive).
• Compare your numerical value to the laboratory’s threshold.
• Account for the date of collection relative to a possible exposure (window period).

Pathologies and phases related to HIV infection

HIV infection is the pathology directly related to this marker. It progresses through several phases if left untreated.

Primary infection (acute phase)

After the virus enters the body, it multiplies rapidly. The immune system reacts strongly. This reaction can cause flu-like symptoms (fever, fatigue, sore throat, swollen lymph nodes). During this phase, the viral load is very high.

Chronic asymptomatic phase

After the acute phase, the virus continues to replicate more slowly. The person usually shows no symptoms. However, CD4+ T lymphocytes are progressively destroyed. This phase can last an average of 5 to 10 years without treatment. Monitoring of viral load and CD4 count is then essential.

Symptomatic phase

As CD4s decline, the immune system weakens. Mild infections can become more frequent or severe. Symptoms may include oral candidiasis, unexplained weight loss, or night sweats.

AIDS (advanced stage of HIV infection)

This stage is reached when the CD4 count drops below the threshold of 200 cells/mm³. The collapse of the immune system opens the door to serious opportunistic infections (Pneumocystis pneumonia, toxoplasmosis) and certain cancers.

Practical advice and medical follow-up

Adapted follow-up schedule

• HIV-negative individuals with risk factors: Doctors recommend screening every 3 months in case of regular exposure. They also advise a test 6 weeks after a one-time risk. Additionally, the concerned person can discuss PrEP (Pre-Exposure Prophylaxis) with a doctor.
• People living with HIV: Regular follow-up is crucial. It includes measuring viral load and CD4 every 3 to 6 months, as well as annual check-ups.

Nutritional recommendations

Good nutrition supports the immune system. It is advisable to favor quality proteins, antioxidant-rich fruits and vegetables, and maintain good hydration. In case of severe immune deficiency, raw foods at risk should be avoided.

When to consult a specialist?

Consult a doctor immediately if:

• You receive a positive or indeterminate test result.
• You have symptoms of primary infection after a risk exposure.
• You live with HIV and develop unusual symptoms (fever, weight loss).

Simple monitoring may be sufficient if your test is negative (outside the window period) and without new risk exposure.

Frequently Asked Questions about HIV

Can the HIV test give false positives or negatives?

Yes, although this is rare. A false negative can occur during the “window period” (before the body produces enough antibodies). 4th generation tests reduce this period to approximately 15 days. False positives are exceptional and always verified by a second confirmation test (such as Western Blot).

How do treatments affect HIV test results?

Antiretroviral treatments do not eliminate antibodies. An HIV test will therefore remain positive. However, treatments make the viral load “undetectable.” This means that the virus is present in such small quantities that it can no longer be sexually transmitted. This is the fundamental principle “U=U” (Undetectable = Untransmittable).

Are there drug interactions with HIV treatments?

Yes, interactions are numerous. Antiretrovirals can alter the concentration of other drugs in the blood, and vice versa. For example, St. John’s Wort, an herbal medicine, can decrease the effectiveness of an anti-HIV treatment. It is therefore imperative to inform your specialist doctor before taking any new medication.

How to interpret an undetectable viral load with low CD4s?

This is a situation of “immuno-virological discordance.” It affects a minority of patients. Even if antiretroviral treatment perfectly controls the virus, the immune system does not fully rebuild itself. This can be due to a late diagnosis or other factors. The prognosis remains good as long as the viral load is undetectable.

Why do some people infected with HIV never get sick?

A very small percentage of people are “elite controllers.” Their immune system naturally controls the virus without treatment. Their genetic peculiarities (notably HLA-B57) are being studied to develop new therapeutic strategies.

Are HIV self-tests reliable?

Yes, self-tests sold in pharmacies are reliable (sensitivity > 99%). They detect antibodies from a drop of blood. However, they have a longer window period (3 months). They are useful for confidential initial screening, but any positive result must be confirmed by a laboratory test.

Conclusion

HIV screening is a fundamental tool in preventive medicine. Understanding what it measures and how to interpret the results is essential.

Key takeaways:

• Early HIV screening is the key to successful management.
• Modern treatments allow for a long and healthy life.
• An undetectable viral load means the virus can no longer be transmitted.
• Research continues to progress towards new preventive and curative solutions.

The “test and treat” approach has transformed individual prognosis and epidemic management. Current scientific advances offer hope for a future where this infection will be even better controlled.

Additional resources

• To deepen your knowledge of this blood marker, click here.
• To extend your knowledge and decipher other markers, more articles are available here.

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