The Package insert for the OraQuick antibody test states, "The OraQuick Advance Rapid HIV-1/2 Antibody Test is intended as an aid in the diagnosis of infection with HIV-1 and/or HIV-2. AIDS and AIDS-related conditions are clinical syndromes and their diagnosis can only be established clinically."
If one is healthy, is it logical to be tested for an infectious disease based on antibodies? The package insert states that a diagnosis is based on "clinical syndromes" not on their antibody test. And yet we take a healthy population...and most pregnant women are a healthy group of people and we test them for antibodies. Healthy people have antibodies--its how our immune system works. It doesn't mean we are ill, it means our bodies picked up the disease and successfully fought it off. Otherwise, we would be sick or dead. But by current medical dogma, if you test positive for hiv, you are sick and will eventually get AIDS. The testing companies know that antibody testing on healthy populations will create a high level of false positives--its the reason for this statement in their package insert. The test was not meant to be a diagnostic. And yet we are using this test on almost all pregnant women. The prenatal clinics (one of the few places where hiv testing is available) in Africa use the number of positives on hiv tests to predict hiv/aids cases in Africa. So they predict an epidemic based on antibody testing. How accurate can that be??? Pregnancy is not a disease...women are going to prenatal clinics not because they are sick but because they want care for a biologically normal condition. One of the reasons for a false positive hiv test is pregnancy. Is antibody testing of pregnant women logical? Seems like a receipe for disaster. Heck the company told us in the package insert that it shouldn't be used as a diagnostic. They have wormed their way out of their liability.
Copyright 2008 Valerie W. McClain
Similar disclaimers are found on most HIV tests. The tests are 'validated' (ironic quotes) through complex reasoning in the hope that by you get to the end of the chain of logic you won't realize it's not grounded anywhere.
ReplyDeleteRapid tests like OraSure/OraQuick are validated by ELISA which is validated by Western Blot. And Western Blot is taken as the gospel. Unless you're negative and they don't think you are, in which case maybe there'll be a viral load test (validated by comparison with antibody tests like ELISA).
It's total scientific garbage. Thanks for raising the issue on your blog.
Dave,
ReplyDeleteI read in a number of documents while researching OraSure that the saliva OraQuick test can be validated by the blood OraQuick test. And vice versa...And OraSure also makes the OraSure Western Blot which is used for validation, too. Valerie
I guess that's what "confirmation" means. "You don't trust test A?", "Well, Test B gives the same results, amazing, huh?". "You don't trust test B?", "Well, test A gives the same results!".
ReplyDeleteReproducibility (two tests giving the same results) is not to be confused with Sensitivity (reacting positively when the thing in question is present) and Specificity (not reacting positively when the thing in question is not present).
The problem with specificity and sensitivity is that you need a 'gold standard' to prove unambiguously that the thing in question is present. With a virus this means purification.