Laboratory diagnosis of HIV Infection

Tests to diagnose HIV infection can be divided into different categories: virus culture, antigen detection, detection of antibodies, and viral genome amplification (PCR).

Sample Collection and Transport

  • For standard HIV-1/HIV-2 antibody testing, a single tube (10 mL) of whole blood is sufficient.
  • Specimens can be stored at room temperature for up to 3 days, and at 4°C for up to 7 days.
  • For longer storage periods, the serum or plasma must be separated from the clot or cells and stored at -20°C.
  • Specimens for PCR generally need to be processed within 48 hours of the collection as viral DNA denatures over time and becomes undetectable.

Virus cultivation

HIV virus can be isolated from infected persons in most phases of the infection. Peripheral blood mononuclear cells (PBMC) can be co-cultivated with activated PBMC from HIV-negative donors in the presence of IL-2. A positive result is recognized by the appearance of the virus antigen (p 24) or reverse transcriptase activity in the culture medium.
Virus cultivation is not done as part of the routine laboratory diagnosis method. 
Course of HIV Infection
Image 1: Course of HIV Infection

Antigen/Antibody detection

Antibodies usually become detectable from 3 to 12 weeks after infection. As a rule, an infected person remains antibody-positive for life, but antibody titers often fall in patients with AIDS (see image 1).
 The most widely applied tests are the indirect and competitive ELISA, using mostly a mixture of viral antigens. It is recommended that confirmatory tests are carried out to exclude the possibility of false-positive results. These are either variations of ELISA tests or Western blot analysis of antibody specificity.
  1. Point of Care tests (POCT) for HIV
    These tests provide rapid, on-site HIV results in a format that is relatively easy to perform.

    Rapid tests for the diagnosis of HIV infection
    Rapid tests for the diagnosis of HIV infection
  2. ELISA for HIV diagnosis
    It is commonly used as a screening assay for many infectious diseases, including HIV.  It is a highly sensitive test but false positives can be seen. The current ‘window period’ (the time from exposure to seroconversion) for HIV is less than three weeks in most cases.
    All HIV diagnostic laboratories must confirm repeated EIA screen-positive results (done by using different parts of the viral antigen ) by a confirmatory assay, usually with Western blot.
    Specimens that screen positive in the first assay but negative in the second assay should still be considered for confirmatory testing if the patient is symptomatic or high risk.
  3. p24 antigen testing
    p24 antigen tests are also enzyme immunoassay  (EIA) based. Antibody is used to capture the disrupted p24 antigen from patient serum.
    P24 antigen test is useful

    • for specimens from patients that are high risk and symptomatic but HIV EIA-negative (for Ab testing), or
    • for specimens that are EIA-positive but Western blot-negative or –indeterminate
    • for confirmation of neonatal HIV infection

Western blot Test

Western blot is a confirmatory diagnosis of HIV infection. It is a highly specific immunoblot that allows for the visualization of antibodies to the structural polypeptides of HIV virus.

Western Blot Test for HIV diagnosis
Western Blot Test for HIV diagnosis

Viral genome amplification (PCR)

The PCR technique represents a major advance in the diagnosis of HIV infection. This powerful technique can amplify the target DNA present in minute amounts. PCR is useful when Ab testing may be insufficient to determine whether a patient is infected
  • in the diagnosis of HIV infection in infants born to infected mothers (presence of maternal IgG antibodies excludes serological testing during the first few months after birth)
  • resolving indeterminate Western blot results and
  • testing immunocompromised individuals who may not mount an antibody response.
Quantitative determination of plasma viremia (virion RNA) by reverse transcription PCR (RT-PCR has become a major tool to follow the progression of HIV infection in untreated patients and monitoring the effects of antiviral chemotherapy in patients. It is used in conjunction with CD4 counts.
CD4+ lymphocyte count
A hallmark of chronic HIV infection is the depletion of CD4+ lymphocytes and the loss of these cells is closely associated with the acquisition of the characteristic opportunistic infections. The monitoring of CD4+ lymphocyte count is, therefore, an important determinant for clinical staging, initiation of antiviral therapy, and Pneumocystis jiroveci pneumonia prophylaxis.

Acharya Tankeshwar

Hello, thank you for visiting my blog. I am Tankeshwar Acharya. Blogging is my passion. As an asst. professor, I am teaching microbiology and immunology to medical and nursing students at PAHS, Nepal. I have been working as a microbiologist at Patan hospital for more than 10 years.

One thought on “Laboratory diagnosis of HIV Infection

  1. Suggestions on the use of antibody blood recovered after aids infection

    Dear ,

    HIV . HBV cure natural product, vaccine manufacturin

    Variants and strains of HIV virus types,
    The total number of patients currently taking antiviral drugs is equal to the DNA structure level.
    The real meaning is that they are consuming sterile antiviral agents that are neglected,
    As it has already appeared, the HIV – 2 mutation is expanding Horizontal.

    aids Not involved in virus types and subtypes,
    The first step is to take samples of cured blood antibodies from patients with aids.
    In other words, current cases of HIV patients should be cured.

    Age, and sex.
    Infection timing and type.

    It cures without distinguishing the above conditions.

    Antibody blood rights after cure is a condition for me to delegate.
    Screening for HIV patients should be conducted by your company.

    Cooperate with your company to manufacture a cure vaccine for HIV infection by collecting blood antibody after cure.
    It is today that your wise judgment is required.

    36 years old male who lives in I guess for less than a year,
    Immune cells 300 or less were detected and the most difficult pneumocysteine in the system as a note in the hospital,
    However, you can be relieved by the use of a negative solution. The date of drinking water solution is 28-8-2017 immediately after hospital confirmation.

    HIV – RNA 245 copies / mL
    Cell Marker Study – CD8 35.6
    Cell Marker Study – CD4 20.5

    Treatment of aids the manufacture of live vaccines is made up of human antibodies.

    HIV , HBV , HCV therapeutic vaccine manufacturing “Antibody production” joint research proposal

    In the future, Accurate cure of viral diseases

    Blood antibody generated after curing the patient and cured internal organs. Skin, and other necessary body parts.
    The attenuated AIDS virus after cure is a viable virus in the manufacture of preventive and therapeutic vaccines
    It can be used as a “base cell” for vaccine production.
    I would like to cooperate with you on this process.

    CD4 + helper and CD8 + cell lysis T cell repair is a natural process.
    Only food you eat daily can kill blood-borne viruses completely.
    This is a natural improvement in antibody production after the virus has completely died.
    Chemicals never make human platelets.
    Platelet production plays an important role in healthy food intake.

    Next, we work with your company to manufacture antibodies for the manufacture of vaccines for HIV (AIDS).

    If the AIDS virus is completely destroyed in HIV patients,
    The production of antibody adjuvants and the use of antibodies is a natural progression.

    aids Know the condition of the patient.

    What is the AIDS virus level?
    How long have you been infected with HIV / AIDS?
    What is the CD-4/8 level of each of the aids patients?
    What is the platelet count of What is the platelet count of patients with aids?

    Mechanism of cure of blood viral disease

    Compressed natural food intake 100 cc per day,
    hepatitis. Type B, Type C) Modified Hepatitis and Subtype Hepatitis Cure
    Liver regeneration of liver cirrhosis is due to replication and proliferation of hepatitis,
    AIDS (HIV-1/2 type) will be cured.
    Concurrent infection HBV + HIV and HIV + HCV are treated correctly.

    With functional beverages, you can:
    The DAN (virus) level is fully regenerated after it begins to die properly.
    The number of platelets that fall is exactly increased.
    It is restored by the precise increase of immune cell number (CD-4/8) in battle with virus.

    After all the above values ​​are returned to normal and the blood and organs have completely died from the virus,
    Antibody production is naturally produced and utilized, and cooperation with patients will be made to manufacture vaccines.

    Weakened viruses can be used as “live vaccine feedstocks for infected cells.”

    We are responsible for the supply of functional beverages that lead to the complete death of the AIDS virus.
    Please select at least 3 to 5 patients who do not distinguish between sexes.
    Functional beverage supply is free of charge until the cure is confirmed.
    It takes 6 to 24 months to determine the antibody for individual differences.

    We will do our best to work with vaccine manufacturers to manufacture vaccines that completely kill the HIV virus.
    Thank you very much.

    Human Blood Virus Institute
    942 Jumunjin Gangneug Gangwondo Republic of Korea
    + 82-10-5239-0404
    Principal Investigator Kim E Rang

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