This quote from Lyme disease: A Look Beyond Antibiotics tells a lot and it most likely isn't just limited to lyme:
Making the history of a tick bite a condition for a physician to be willing to even consider the possibility of a Bb infection seems cynical and cruel. To use conventional diagnostic tests such as the Western Blot, one has to think in paradoxes: the patient has to be treated with an effective treatment modality first before the patient recovers enough to produce the antibodies, which then are looked for in the test. A positive Western Blot proves that the treatment given worked to some degree. A negative Western Blot does not and cannot prove the absence of the infection. Having taken another route altogether, we have recognized that today many if not most Americans are carriers of the infection. Most infected people are symptomatic, but the severity and type of the symptoms varies greatly. The microbes often invade tissues that had been injured: your chronic neck pain or sciatica really may be a Bb infection. The same may be true for your chronic TMJ problem, your adrenal fatigue, your thyroid dysfunction, your GERD and many other seemingly unrelated symptoms. Many Bb symptoms are mistaken for problems of natural or premature aging.