Hanson,
Having researched the IGeneX/ILADS neck of the woods fairly extensively when I had disseminated Lyme myself, (I'm not the PALS), I would not regard your lab result as conclusive evidence of Lyme, particularly if both ELISA and Western Blot were completely negative on multiple occasions and you've had three reputable diagnoses of ALS based that included EMG/NCV testing. If you have ALS, it will progress and be unmistakeable. I would not begin any antibiotic or supplement course based on the supposition that you have Lyme based solely on this result, nor on the word of any "LLMDs." However, if you have significant symptoms that do not fit into the ALS differential, that began in the purported ALS onset period, I would discuss those with both your neuro(s) and an infectious disease specialist (one who treats all IDs, not just Lyme), as well as an internist.