best lab to test for co-infections?

I've heard that testing for co-infections isn't always going to be accurate, for similar reasons as testing for lyme

and I understand and agree that to be a with a lyme doctor who can recognize symptoms of the co-infections and treat according to those is best, and ideal,

but, all that said, for a couple of different reasons that would make this post a lot longer, and so for now I'll just skip, I'm considering having my son tested for co-infections, maybe especially Bartonella (due to some symptoms that show up a lot in Bart. symptom lists i.e. sole of foot pain, stomach pain, forehead headaches, irritability.

so, anyway, from what I've read it sounds like Igenex is best, and maybe galaxy lab?

but there's a quest lab in town and looks like insurance would cover it. Is it a waste of time? insurance sure would be helpful (of course)
I suppose it all depends?

anyway, any thoughts are always appreciated!
thanks!

I have read a geimsa stain is best for babesia. I personally feel igenex is the best test. I had 3 different lab test done by conventional labs, all negative only by igenex showed positive for lyme and babesia. my bartonella was negative tho, altho I think I may have it.