Forgive me, I've been gone for a week, so I may have missed something, but why are you waiting another month?
An IgM result means that you have an active infection. It once was thought to mean an 'early' infection, but has since been revised. IgG means that the infection is at a later stage, which is why I'm confused as to why you are waiting another month.
As for the tests, they are not that random at all. Each band and each species of bacteria will react in a specific manner. Here is the site that I use to help interpret them:
www.oocities.org/hotsprings/oasis/6455/western-blot.txt You can go there to find supporting Pubmed articles showing what these bands represent.
The Western Blot can be used to perform tests for many different bacteria. I don't know enough of the specifics to be able to explain it in detail of any sort, but I do know that a "Lyme specific band" means specific for Borrelia Burgdorferi, sensu stricto - Lyme disease in the strictest sense. There is only
one on the over 300 known strains of Lyme that is considered Bb, ss. Nothing else will turn a Lyme specific band positive other than Lyme disease - - even though there are over 100 different strains of Borrelia in the US that cause human illness.
The only bands that I'm aware of that are known that they can cross react is Bands 18 & 41 (whether in IgM or IgG) because they are indicative of the tail of the bacteria, which can cross react with other Spirochetal bacteria such as Relapsing Fever, Pintas and Yaws, and Syphilis.
Recently (less than 2 years), some people have decided that band 31 no longer is Lyme specific, which really makes no sense when you realize just how many studies have been done and how many articles have been written showing that it is indeed Lyme specific:
Band 31:
www.ncbi.nlm.nih.gov/pubmed/1520966www.ncbi.nlm.nih.gov/pubmed/9440203www.ncbi.nlm.nih.gov/pubmed/8406878www.ncbi.nlm.nih.gov/pubmed/8005219www.ncbi.nlm.nih.gov/pubmed/10030131And more references can be found here:
www.reocities.com/HotSprings/Oasis/6455/western-blot.txtAs for band 39, there's even stronger evidence that it is Lyme specific - again, you can go to the link above to see these articles - and there may be more by now if you cared to search for them.
I do hope that this has shined some light on some more information that you can use to help you decide what path is right for you and your son.