Hi wbolyard and welcome.
Igenex is very commonly used especially in North America.
Other labs do exist and are sometimes used - Stonybrook in NY, Armin labs in Germany, etc.
You do need a physician to sign the req forms and the test results are sent to that physician.
Armin labs does not require a physician to do the req - you can get it done yourself. However, if a physician requests it, they can also request a 25% discount.
In Canada you would need to get your blood drawn at a lab and then send the blood to the Igenex lab through courier to arrive during the week so your blood doesn't sit over the weekend while they are closed. So it's recommended you do the blood draw on a Mon or Tues. The courier and lab charges are extra.
I read on here that some people who are close to the lab in the US went there for the blood draw.
Igenex was in my experience, extremely responsive, customer service excellent and the test results were available much faster than they said - after one week.
Girlie's advice is correct. However, they recently (late 2017) offered a new Borrelia immunoblot test as well (325 and 335) which are supposed to be better. I did a full tickborne panel++ which cost me $1800 CAD all things added up - sadly if I'd known what I know now, I wouldn't have spent that much.
Are you able to share a bit why you are testing?
For myself, it was a desire:
to confirm my suspicion that I was suffering from Lyme and
to obtain medical care.
However, the thing to note is that all the Lyme tests available currently aren't very good at catching Lyme or the co-infections - especially in people who have suffered for years and years and considering the sheer number of strains of nasties. That is why LLMDs do a clinical diagnosis and don't rely on lab tests.
My test results were interesting - it told me that I had some kind of bacterial infection (ongoing and old) and that a protein specific to Borellia was found - but it didn't meet the standards for a positive. I know a couple of other Lyme sufferers who did not get a positive from the test - one got a positive on Babesia but not Borellia, one got results similar to mine (she did subsequently get a positive through Armin labs though). I also know people who got positive results by both CDC and Igenex criteria and this allowed them to access medical care here.
Having said that, the test result gave me the confidence to pursue treatment. However, what gave me the full confidence that I was indeed suffering from Lyme were other things - meeting other Lyme patients who had almost all similar symptoms, being treated by a doctor whose eyes didn't glaze over and who was certain I had Lyme based on my clinical presentation, and finally the fact that I started recovering after treatment - hard to argue or doubt proof that lies in the pudding.
What I'm trying to say is why do you need the result? If it is not a requirement to access medical care - you may be better off saving your money. I would suggest taking the Horowitz MSIDS screening questionnaire and then approaching a LLMD if that's why you're doing it.