HIV Test after 11 days : which test to do

Published Date : 2023-09-08T20:54:05.696Z

Updated Date : 2023-09-08T20:54:05.696+00:00

How does the HIV virus multiply inside the body

Upon exposure to the HIV virus, replication starts within submucosal cells. The virus establishes contact with CD4 helper T cells, essential components of the immune system. Subsequently, viral RNA, carrying the virus's genetic information, enters these CD4 cells. Reverse transcriptase catalyzes the conversion of viral RNA into viral DNA. This viral DNA takes charge of the cellular machinery, guiding it to produce an increased number of viral particles. Ultimately, the infected cell's capacity is surpassed, leading to its rupture and the release of newly formed virions into the bloodstream.

What viral particles are in the body around 11 days after exposure?

At 11 the viral RNA may be detectable, since RNA multiplication is already evident at this stage.

The HIV Virus comprises of four detectable markers : HIV RNA, HIV P24 antigen, HIV IGM Antibodies and HIV IGG ANTIBODIES

What is a window period?

A window period is the time interval that must elapse for HIV tests to provide accurate results, taking into account the body's ability to generate detectable markers.

Which are the different tests that can be done to detect HIV?

Detection of HIV is possible through a range of tests that focus on different virus components. These include tests specifically designed for the p24 antigen, antibodies like IgM and IgG, and the highly sensitive RNA PCR tests.

Third Generation Tests

3rd generation tests are so called because they detect antibodies to the HIV 1 and HIV 2 strains. These tests are available in two formats - lab based automated assays, which automate the processes of pipetting and dispensing and point of care assays that can be done using standard manual pipetting.

Fourth Generation Tests

4th generation tests are so called because they detect both the HIV P24 antigen as well as antibodies to the HIV 1 and HIV 2 strains. These tests are available in two formats - lab based automated assays, which automate the processes of pipetting and dispensing and point of care assays that can be done using standard manual pipetting.

Will a 4th generation lab based test detect HIV at 11 days?

There is a moderate chance of a 4th generation lab based test being able to detect the virus in your body on day 11 after exposure to the HIV virus. This is because the analytes measured by this test, namely - p24 antigen, IgM and IgG antibodies are not yet present in adequate concentration in your blood by day 11 of the infection.

A 4th generation HIV test is a state-of-the-art screening tool capable of detecting both the p24 antigen and IgM/IgG antibodies concurrently, improving accuracy..Lab based assays as described above are fully automated and are considered to be one of the most sensitive tests for early diagnosis of HIV. If you were exposed to HIV, there is a 25.5% chance that the 4th generation lab based assay will be able to detect the virus at 11 days. This is based on the varying levels of the p24 antigen as well as the time it takes for the antibodies to develop in the body agains the virus. It is recommended that you retest after some days since the chances of detecting HIV increase with time.

Will a 4th generation Point of Care based test detect HIV at 11 days?

There is a low chance of a 4th generation point of care based test being able to detect the virus in your body on day 11 after exposure to the HIV virus. This is because the analytes measured by this test, namely - IgM and IgG antibodies are not yet present in adequate concentration in your blood by day 11 of the infection.

.Point of care assays as described above are generally performed with methods like lateral flow immunochromatography and are well suited for low resource and bedside settings. These assays have now achieved comparable results to lab based assays. If you were exposed to HIV, there is a 24.8% chance that a 4th generation point of care based assay will be able to detect the virus at 11. This is based on the varying levels of the p24 antigen as well as the time it takes for the antibodies to develop in the body agains the virus. It is recommended that you retest after some days since the chances of detecting HIV increase with time.

Will a third generation lab based assay detect HIV at 11 days?

There is a low chance of a 3rd generation lab based test being able to detect the virus in your body on day 11 after exposure to the HIV virus. This is because the analytes measured by this test, namely - IgM and IgG antibodies are not yet present in adequate concentration in your blood by day 11 of the infection.

The 3rd generation HIV test is an established diagnostic technique that simultaneously detects IgM and IgG antibodies against the virus, aiding in timely diagnosis..Third generation assay only test for the IgM and IgG antibodies, as such the latency for positivity with these assays is greater. Third generation lab based assays use automation in various steps of the test and as such are considered to be more accurate than the point of care tests, however they require more expensive equipment. If you were exposed to HIV, there is a 22.9% chance that a 3rd generation lab based assay will be able to detect the virus at 11 days. This is based on the time it takes for the antibodies to develop in the body agains the virus. It is recommended that you retest after some days since the chances of detecting HIV increase with time.

Will a third generation point of care based assay detect HIV at 11 days?

There is a low chance of a 3rd generation point of care based test being able to detect the virus in your body on day 11 after exposure to the HIV virus. This is because the analytes measured by this test, namely - IgM and IgG antibodies are not yet present in adequate concentration in your blood by day 11 of the infection.

.Third generation assay only test for the IgM and IgG antibodies, as such the latency for positivity with these assays is greater. Third generation point of care based assays use lateral flow chromatography or similar techniques and are suited for low resource settings. If you were exposed to HIV, there is a 18.3% chance, that a 3rd generation point of care based assay will be able to detect the virus at 11 days. This is based on the time it takes for the antibodies to develop in the body agains the virus. It is recommended that you retest after some days since the chances of detecting HIV increase with time.

Will a RNA PCR test detect HIV at 11 days?

There is a moderate chance of a RNA PCR Molecular Test being able to detect the virus in your body on day 11 after exposure to the HIV virus. This is because the analytes measured by this test, namely - HIV Viral RNA are not yet present in adequate concentration in your blood by day 11 of the infection.

RNA PCR assays can detect viral loads as low as 20 copies of viral RNA/ml. RNA PCR assays can detect the virus as early as 10-12 days, and almost all patients will show positivity between 20-30 days.Based on the fact that you have been exposed 11 days ago, there is a 45.8% chance of the RNA PCR test being able to detect the virus.You should retest after some days, for confirmation.

What is the confirmatory test for HIV at 11?

There is no 100% confirmatory test for HIV. Any negative test is recommended to be repeated after 45-90 days. Positive tests are usually reconfirmed on repeated sampling in accordance with the guidelines of your country's health organizations. While the RNA PCR test usually has the highest chance of detecting the virus, it is never recommended as a first line test, owing to its cost and complexity. A first line screening test is usually done (4th generation) and if it is positive, additional testing is recommeded.

References

• Hurt CB, Nelson JAE, Hightow-Weidman LB, Miller WC. Selecting an HIV Test: A Narrative Review for Clinicians and Researchers. Sex Transm Dis. 2017 Dec;44(12):739-746. doi: 10.1097/OLQ.0000000000000719. PMID: 29140890; PMCID: PMC5718364.Hurt et,al
• Kevin P. Delaney and others, Time Until Emergence of HIV Test Reactivity Following Infection With HIV-1: Implications for Interpreting Test Results and Retesting After Exposure, Clinical Infectious Diseases, Volume 64, Issue 1, 1 January 2017, Pages 53–59,Delaney et.al