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Thread: The end for Western Blot?

  1. #1
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    Default The end for Western Blot?

    Am I reading this correctly? It looks like the WB will no longer be "orderable" from LabCorp. This is from another patient.

    LabCorp "accidentally" did a WB on me last month, and there's no similar notation on my report from them.
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  2. #2
    Jibrail is offline Contributing Member (10-99 posts)
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    Default Re: The end for Western Blot?

    It may be related to this press release :
    LabCorp Announces the Availability of a 4th Generation HIV Assay to Allow the Earlier Detection of Acute HIV Infection.

    A 4th generation test is nothing new (it is used for years, I can't say exactly for how many but in the 2000's), it was meant to detect simultaneously the so-called HIV antibodies and antigens. The aim was to detect "HIV" earlier, to reduce the "seroconversion window", especially for screening test (blood donors...). They have taken the place of the Anti-p24 only test to dectect so-called early seroconversion, which are not used anymore (at least in US or EU). But it looks like an improved ELISA+p24, and cannot substitute for Western Blot.

    It seems there are now "advanced 4th generation tests". On the third page of this document, it could be seen that the "HIV" diagnosis could be done without Western Blot, but with a "HIV" proteins antigens research instead.

    I'm not familiar with this, but I guess that just like for p24, antigens could be detected earlier than antibodies, but it's likely it wasn't as reliable as antibodies detection. Maybe this is not the case anymore.

    This is an important subject for us and I think we must look forward and be aware of what it could mean.

  3. #3
    cdm is offline Veteran Member (100+ posts)
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    Default Re: The end for Western Blot?

    Quote Originally Posted by Jibrail View Post

    I'm not familiar with this, but I guess that just like for p24, antigens could be detected earlier than antibodies, but it's likely it wasn't as reliable as antibodies detection. Maybe this is not the case anymore.

    This is an important subject for us and I think we must look forward and be aware of what it could mean.
    Nothing to worry about. It would be the same if you said that garbages are seen a few hours earlier than the garbage collectors

  4. #4
    Jibrail is offline Contributing Member (10-99 posts)
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    Default Re: The end for Western Blot?

    Quote Originally Posted by cdm View Post
    Nothing to worry about. It would be the same if you said that garbages are seen a few hours earlier than the garbage collectors
    It's not just that. They use the "time - window" argument to cover something else. Western Blot has always been criticized, because it's long and expensive to perform. But it's also more precise and can help not being tested positive; and the tested people can know the details of the positive and negative antibodies - PG have shown us how it matters. It's far better than to have just a Viral Load test as a confirmatory test (after a positive ELISA) to "prove" someone being positive or not. Much more people would have been tested positive using such tests.

    When you read this paper about the new ways of testing, you can fear that the future "HIV" tests could be even worst than today : they describe Western Blot as a dying old "pet", mocking labs "reluctant" to abandon it, and thinking instead about using VL as a confirmatory test...

    Some laboratories may be reluctant to let go of another test. Dr. Pandori mentions another question that arose during the conference calls—and it’s one that makes him laugh. Hard. “Do I have to use the Multispot as my confirmation, or can I keep using the Western blot? My staff love Western blot.“

    Western blot doesn’t need to be banished, say the guideline’s creators. No algorithm is perfect, and Western blot can still be used to sort out diagnostic dilemmas. If a person is positive on the Multispot assay, for example, the next step would be a viral load test. If that’s negative, then what? Turn to the Western blot, Dr. Branson suggests. “We have solid evidence that in antibody-positive people—that is, people who are EIA positive and Western blot positive, between three and five percent will have negative HIV-1 RNA tests.“

    But even if Western blot isn’t racing off into the sunset, it may have a diminished role as a supplemental test. Dr. Werner talks about Western blot the way one might speak of a well-loved pet whose end is drawing nigh. “It’s been a good assay,“ she says. “It had a lot of good years, and it’s still good for longstanding infections. But it’s no longer as useful as it once was in the role as a supplemental test.“
    I may be wrong but if it comes true I feel there's something to worry about.

  5. #5
    Jibrail is offline Contributing Member (10-99 posts)
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    Default Re: The end for Western Blot?

    As reported by M. Aziz in the Joan Shenton's website (Immunity Ressource Foundation), it seems that this time "HIV" Western Blot assay is now passing away, at least in the US.

    If I interpret correctly the updated CDC guidelines for HIV diagnosis testing, CDC have just dropped the Western Blot HIV Test as a mandatory confirmatory test. Now, two different assays from different manufacturers would be sufficient to diagnose "HIV", and among them we can find Elisa test, p24 antigenemia and nucleic acid testing (NAT - viral load).

    It means that two positive Elisa from different manufacturers, or a positive Elisa and a detectable "HIV" viral load, or a positive Elisa and a positive P24 antigenemia would be sufficient to diagnose an "HIV" infection. Western Blot test would be now just an option, and as it's more expensive, it's not likely to be done anymore, at least as the normal, routine confirmatory test.

    Two papers published by Bernard Branson from the CDC are cited in the updated CDC guidelines, in 2010 and 2011. It appears that his main concern is to detect seroconversion as early as possible, aiming to treat patients earlier, to break the transmission chain, as "the risk of transmission from persons with early infection is much higher than that from persons with established infection". But in the same time, he underscores that "the Western blot and line immunoassays remain essential for resolving vaccine-induced seropositivity and clinically useful for monitoring the evolution of seroconversion".

    Now with such questionable diagnostic tools as p24 and VL, which lower the hurdle for a positive diagnostic comparing to the WB, one would expect that the "HIV" seroconversion rate rises again... It would be interessant to know what will happen in the other countries also using WB; in France where I live, the 2013 updated guidelines didn't drop WB yet.

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