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test results must be confirmed by doing another test on the person’s blood, called a Western Blot, sometimes referred to as an Immunoblot; and at last, after some had waited as long as two years, 50,000 people were told they were really not HIV-Positive after all! Imagine what they went through, thinking they might be Positive all that time. And think of the hundreds of thousands of other people – their families, their sexual partners, their friends – who went through hell with them. It was truly criminal what we did to these people.”Campbell wants to try to keep Tanner’s emotions out of the testimony. “And the Western Blot was supposed to solve this problem?”
“Let’s be very clear, because this is an important point. The Western Blot was originally designed and intended to find all the false positive reactions created by the ELISA, not to confirm the positive ones.”
It’s a good point, and I’ll come back to it later. “Dr. Tanner, please tell us what a Western Blot is.”
“Like the ELISA test, it is a test to detect antibodies to HIV in a person’s blood.”
“And how does the HIV Western Blot work?”
“Very simply, you take proteins from what is supposed to be the Human Immunodeficiency Virus, combine them with a person’s blood, and if the test changes color, you are said to be positive for that protein’s antibody.”
“That sounds just like the ELISA test. So what’s the difference between the HIV ELISA test and the HIV Western Blot?”
“First of all, in the ELISA, all the proteins from the so-called HIV are mixed together, kind of like a big soup. When the test is positive, you don’t know exactly what protein or proteins reacted. In the Western Blot, the proteins are separated into different strips, or bands – one for each protein – so you can see exactly which protein or proteins reacted to the person’s blood. Secondly, the ‘change of color’ I mentioned is different than an ELISA, in that it’s not really the color change that’s important, but the formation of blots on the bands that signify a reaction.”
“Why would that be useful – to see which proteins reacted and which didn’t?”
“When the ELISA test was getting