Technically, Lyme is a clinical diagnosis. Lab work is diagnostically supportive. But outside of the classic bull's eye EM rash, no symptoms are Lyme-specific, not even swollen knees (back in the mid '70's in Lyme, Ct there were a cluster of cases of children with swollen knees that were at first diagnosed with Juvenile RA - and we all know how that story ended.)
So lab work is important to help either confirm Lyme or rule it out.
That's where some of the problems really crystallize. For surveillance purposes, 20 years ago researchers decided that five out of ten bands - visible antibody reactions - had to be captured thru what's called a Western Blot for a case to be labeled Bb positive (this is for IgGs. For IgM's, i.e.acute cases, it's two of three bands). Remember, the algorithm generated for that threshold was meant for surveillance purposes only, originally.
That is not what happened, however. Instead, over time clinicians and researchers adopted the Dearborn, Michigan recommendations as diagnostic, almost as if through a default mechanism. Worse, thanks in great measure to the introduction of a Lyme vaccine, two very important bands - OspA (band 31) and OspB (band 34) - were yanked from consideration. So when labs such as Labcorp or Quest run blood work to check for Lyme, they do so without tapping those two Borrelia-specific bands.
In theory, accordingly, I can have WB results that come in at four bands IgG positive, and therefore be told by my doctor I do not have Lyme. That same test with my blood work, if run by IgeneX , apparently would include the two jettisoned Bands, 31 and 34, and if one of them appeared - BAM! I am Lyme positive. Don't forget, the purpose of the WB and its very specific band identification process is to help clinicians boost the confidence level of a Lyme diagnosis. Period. So, well, as a patient, if I can see I've tested positive for Bands 31 and 34 - I'm not sure I really care about the stupid algorithm - I've ratcheted up my confidence level that I have Lyme, and I may wish to act on that.
So, it is worth it for some patients to include those two extra bands. Unfortunately, it is very much a numbers game. I don't even know if such results, i.e. including either OspA or OspB, would be recognized by the CDC because of the implications to the algorithm that was embraced so many years ago. In my opinion they SHOULD be if only because the purpose of the test - of any current Lyme diagnostic - is confirmatory only.
Whew. This is way simplistic. I didn't even touch on that odd prerequisite, the ELISA. And there are other reasons many turn to iGeneX, some of which Roxie60 touched upon. Regardless, many IDSA supporters frown on the lab because of what they consider liberal interpretations, and the risk of generating too many false positive readings.