The routine blood test that your local lab does for Lyme is fairly unreliable, and even more so when it comes to certain co-infections, especially Babesia. A close cousin with malaria, you don't want that red blood cell killer in your body, so you'll want to know if it's there.
Fortunately, there are a few "fairly"reliable methods and labs for testing. Igenex is a good lab to start with but if you test negative and yet have symptoms of Lyme or Babesia, you might want to go further and seek out a competent ART (autonomic response testing) practitioner. ART testing is highly accurate if done correctly and is a fast, easy, inexpensive way to test. E-mail me if you need a referral in Washington State for an ART practitioner. Practitioners who do it right can be hard to find.
Beyond that, Bowen Labs is another good choice, which relies upon a positive identification of the Bb spirochete and the Babesia parasite (although it only identifies a few species of Babesia, and there are many). Then there is Igenex, which relies upon the identification of antibodies to Bb and Company. Igenex is a good place to start, but many Lymies won't produce antibodies to the illness, so if you don't get a positive reading through Igenex, it doesn't necessarily mean you don't have the bug! (and keep in mind that an "Indeterminate" reading is thought by some Lyme specialists to be a weak positive) . So go for Bowen, or ART. You may want to test more than once if you still come up with negative results. There are other methods out there, ie, DNA testing, but we'll just keep it simple for now...If you don't have the cash or ability to test for these infections, but suspect you have Lyme, you can always do a trial run of a treatment and determine, based on Herxheimer response, whether the infection is present.