So you've sent your blood away to sunny California (...don't you wish it were YOU instead of just your blood?!) and now you have the results in hand. You're thinking, "YES!!!...Now I'll know if I have Lyme disease!" You take one look at those papers, scratch your head, and end up right back where you started.....knowing nothing!
The IGeneX results can be a tad difficult to decipher for those of us who are not infectious disease doctors. But you've come to the right place. I'll teach you how to sift through the information on your Western Blot and make some sense out of it.
The Western Blot IgM and IgG are the most "telling" of your tests. If you can only afford to do one test, this one is a MUST. Your IGeneX Western Blot result will be in this format. This was my Western Blot IgM from March 2011.
Click image to make larger
Here is the basic information you will need to make heads or tails of this test result.
Are you POSITIVE or NEGATIVE for Lyme?
Take a look about half-way down the page, right above the list of numbers (which are the various "bands" tested.....more on that later.) There is where you will find the words POSITIVE or NEGATIVE.
What does IgM and IgG mean?
The Western Blot tests your blood for antibodies made against the Borrelia burgdorferi bacteria (aka Lyme disease bacteria). Antibodies for all infections are classified into 2 types: IgM and IgG. IgM antibodies are the first antibodies that your body manufactures and they indicate recent infection. IgG antibodies are manufactured later, and indicate an older (most likely resolved) infection. With most infections, the presence of IgG antibodies indicates immunity because the infection has cleared up, but the "memory" of it is still there in the form of IgG antibodies. This is why there are 2 separate Western Blot tests for infections, including Lyme.
Now in the case of Lyme, there is a situation that many physicians will not be familiar with, unless you are a Lyme specialist. Even if you have a long-term Lyme infection, and are in a chronic state, you might still produce IgM antibodies (which would normally indicate recent infection) because the body continually recognizes the bacteria as a new infection. This information is not critical for you to know right now, but it's just an FYI. (If you want to pursue more about this topic, check out LymeMD.)
So what does that list of numbers mean?
Borrelia burdgorferi does not cause the production one single antibody. Rather, many different antibodies can be produced against the various proteins found on the surface of the bacteria. These proteins are labelled by their weight, which is measured in kDa (kilodaltons). When your blood is tested, the technologist is looking for a reaction to all of these different proteins (aka "bands"). Bands which are very specific to Borrelia include 18, 23-25, 28, 30, 31, 34, 39, 58, 66 and 93.
You will notice that the antibody reactions are noted by +/- signs or the word IND on the test result. This indicates the intensity of that particular antibody on the test strip. The darker the band appears, the greater the number of + signs, meaning the greater the number of antibodies in your blood. IND means indeterminate, which means that "something" showed up, but it was not dark enough to classify with one + sign.
Here is a picture of what a test strip looks like, showing bands of varying intensity. The source for this picture is Jemsek Specialty Clinic.
For further reading on this topic, check out Dr. Charles Crist and LymeMD. A list of the various proteins/bands and how they relate to the Lyme bacteria can be found here.
IGeneX Results VS. CDC Results
So why are there 2 results reported, one for the IGeneX Lab and one for the CDC (Centers for Disease Control)? That is because the criteria for declaring a positive differ between IGeneX and the CDC. The CDC have narrower criteria; in other words, it is harder to get a positive from the CDC than it is from IGeneX. The explanation of the criteria is in the first paragraph of the test result.
I know what you're thinking.....The IGeneX Lab must have broader criteria because they want to produce a greater number of positives. They're in the "business", after all!
That is not at all the case.
Here is a bit of history. There was a Lyme vaccine produced and administered in the 1990s which was formulated from the 31 kDa protein. Clearly, anyone who had received a vaccine would register positive for band 31 on a Western Blot. This posed a problem in that people would receive "false positive" results. So, in 1994, in order to prevent skewing the statistics for positive cases of Lyme, the IDSA removed bands 31 and 34 from the Western Blot even though they are highly specific for Lyme disease. Once again, this was done for purposes of surveillance, that is, reporting cases of Lyme and keeping track of statistics. It has nothing to do with diagnosis. Yet, most of the standard Western Blot tests done by ordinary labs do NOT report on these significant bands on their Western Blots.
IGeneX tests and reports on ALL of the bands, thus giving a more accurate picture of the antibodies in your blood. This is why IgeneX declares if you are positive according to their criteria AND according to CDC criteria. Honestly, getting a positive from the CDC is akin to winning the lottery....so if it's negative, take it with a grain of salt. The IGeneX result has more credence in my opinion.
Complicated....I know! Is your head spinning, yet? And there's so much more history to tell in order to fully explain all of that, but this is just "Western Blot 101". For the advanced course in Lyme disease, I highly recommend Pamela Weintraub's book, Cure Unknown.
My Test Results
You can click on the image above to view my test results. Check out the intensity of my 31 band! (+++) That's a very high intensity, and that is for a very highly specific band associated with Borrelia (the one they made the Lyme vaccine from, remember?) Is there any doubt that I have been exposed to Borrelia? That band alone, along with my bizarre symptoms, is certainly enough for a positive diagnosis. But I had two other positive Lyme specific bands, and one IND. Case closed. There is no doubt in my mind, or my LLMD's, that I have Lyme disease.
Does NEGATIVE mean that you're negative?
Well, not always! My first LLMD said that sometimes the sickest patients have negative results, even from IGeneX. There are various factors involved. If the test was done too soon at the beginning of infection, for example, there may not have been enough time for the body to produce a sufficient amount of IgM antibodies for a test to pick up. There are many other reasons, too. And sometimes we just don't know why.
And this is the reason why Lyme-literate doctors state that Lyme disease is above all a CLINICAL diagnosis based first and foremost on symptoms, history, and risk of exposure, with blood work playing a minor role.
Additional information can be found in this blog here.