What if a person has HIV but his/her viral load is at an 'undetectable' level?

[kraam]

Which cannot be detected by the 4th generation rapid test kit or even the laboratory tests?

Meaning to say that if the person had tested using the 4th generation rapid test kit and it showed a 'negative' result, but the person has HIV in him/her? Is that possible?

See here for more info

http://betablog.org/undetectable-bur...ions-answered/

[Armpits]

your are talking about the window period or false negative issue?

[jitaokenaburn]

Viral load is viral load. The 4th Gen Rapid test and other lab test are screening tests that looks for HIV antibodies. Totally different thing. When a person acquires a virus, specific antibodies are created to fight it. The creation of this specific antibody means that we can test whether a person has contracted the virus before, even after the virus itself has been subdued or reduced to a very very small amount. A close example would be Chicken Pox (Varicella Zoster). Even though you had it briefly when you were young, if you were to test for the antibodies now you would still show up positive. The chicken pox virus, like HIV cannot be cured but can be reduced to almost undetectable levels when dormant so if you try to PCR/DNA test for the virus itself it would come up as "undetected".

So to summarize:

1) To find out a person's HIV status, screening tests are used like the 4th gen rapid or laboratory tests that determines a person's status based the presence of HIV antibodies.

2) To find out how much HIV virus is present in the person, the viral load test is used to determine the load (amount) of virus in the bloodstream.

3) HIV positive individuals will always show up positive in the screening test regardless of viral load

4) HIV negative individuals do not need to worry about "having an undetectable viral load" causing their screening test to be wrong, or being exposed to a HIV positive individual who is negative due to "having an undetectable viral load".

The window period / false negative is a whole other issue.

[DoctorTan]

Originally Posted by jitaokenaburn

Viral load is viral load.

Excellent answer.

[peanut123]

The only thing I'll add to this explanation is that the 4th Gen HIV test kits test for both antibodies AND antigens (p24 antigen).

http://afa.org.sg/what-is-a-4th-gen-hiv-test/

Originally Posted by jitaokenaburn

Viral load is viral load. The 4th Gen Rapid test and other lab test are screening tests that looks for HIV antibodies. Totally different thing. When a person acquires a virus, specific antibodies are created to fight it. The creation of this specific antibody means that we can test whether a person has contracted the virus before, even after the virus itself has been subdued or reduced to a very very small amount. A close example would be Chicken Pox (Varicella Zoster). Even though you had it briefly when you were young, if you were to test for the antibodies now you would still show up positive. The chicken pox virus, like HIV cannot be cured but can be reduced to almost undetectable levels when dormant so if you try to PCR/DNA test for the virus itself it would come up as "undetected".

So to summarize:

1) To find out a person's HIV status, screening tests are used like the 4th gen rapid or laboratory tests that determines a person's status based the presence of HIV antibodies.

2) To find out how much HIV virus is present in the person, the viral load test is used to determine the load (amount) of virus in the bloodstream.

3) HIV positive individuals will always show up positive in the screening test regardless of viral load

4) HIV negative individuals do not need to worry about "having an undetectable viral load" causing their screening test to be wrong, or being exposed to a HIV positive individual who is negative due to "having an undetectable viral load".

The window period / false negative is a whole other issue.

[kraam]

If the HIV virus initially enters the person's body, but it is at a low, 'undetectable' level, thus the body is not able to produce antibodies and also a low number of antigens, thus escaping detection by the 4th gen test kit.

Is this scenario possible and if not, why?

[jitaokenaburn]

There is an incubation period for the virus before the antigens and eventually antibodies are formed, so yes that scenario exists. This is called the window period. Anyway within 5-15 days the P-24 antigen starts to form already and it is part of the 4th gen test.

[kraam]

[DoctorVChia]

Originally Posted by kraam

If the HIV virus initially enters the person's body, but it is at a low, 'undetectable' level, thus the body is not able to produce antibodies and also a low number of antigens, thus escaping detection by the 4th gen test kit.

Is this scenario possible and if not, why?

Hi Kraam

The "4th generation test" tests for the P24 viral antigen and HIV 1/2 antibodies. It doesn't check for the "viral load."

By the way, in my blog post below I talked about the "second window" period for the 4th gen test:

http://elyonclinic.com.sg/hiv-testin...linics-part-2/

So it's possible for a patient to be tested negative and yet has HIV.

Cheers!

[kraam]

Originally Posted by DoctorVChia

Hi Kraam

The "4th generation test" tests for the P24 viral antigen and HIV 1/2 antibodies. It doesn't check for the "viral load."

By the way, in my blog post below I talked about the "second window" period for the 4th gen test:

http://elyonclinic.com.sg/hiv-testin...linics-part-2/

So it's possible for a patient to be tested negative and yet has HIV.

Cheers!

Finally someone got my point.

Thanks doc.

[DoctorVChia]

Originally Posted by kraam

Finally someone got my point.

Thanks doc.

You are welcomed.

Also, be cautious of claims that the rapid HIV Combo/Duo test is "conclusive" at 28 days.

See my posts on this issue:

http://elyonclinic.com.sg/is-the-rap...uk-guidelines/

http://elyonclinic.com.sg/is-the-rap...iv-guidelines/