Based on the Huggins research published in the book, "It's All In Your Head", a low hair mercury level can indicate long-term chronic mercury exposure through amalgams in stage 2.

In other words, according to the research, people who are in stage 1 would have high blood mercury levels and thus have mercury show up in the hair.

In stage 2, the body begins compensating in numerous ways and blood mercury levels go down and thus hair mercury decreases too and can show up very low. You may still be experiencing chronic exposure, it's just that the body is managing to keep blood mercury levels low in order to protect itself.

In stage 3, the body can no longer compensate and blood mercury levels again shoot up and this is when people begin experiencing dramatic symptoms over just a period of months or a few years, even though the amalgams have been in for 10, 20, or even 40 years.

At this point, hair mercury will again rise and be detectable with hair analysis. Therefore, hair mercury analysis are generally high in stage 1 and 3 and low in stage 2. Stage 2 is, by far, the longest occuring stage of mercury poisoning from long-term exposure to amalgam fillings

Some doctors recommend a urine-based DMPS challange test, but others recommend against because it can redistribute existing mercury throughout the body and facilitate more damage. It is, nevertheless, easy and inexpensive.

I elected to have mine removed because I had enough of the symptoms to convince me that this was indeed the problem. Of course, my recovery was dramatic. If you're interested, you can read about it here:
My Mercury Story

Because mercury interacts with the body in so many different ways, and because it causes such diverse symptoms, it can be hard to detect. Here is an excerpt from the book, "It's All In Your Head" which describes a number of the possible signs. Please note that due to the complexity of the symptoms, the book notes that mercury diagnosis is often a "professional judgement call", I also believe, given numerous symptoms, it could be considered common sense.

o A white blood cell count above 7,500 or below 4,500

o Hematocrit above 50% or below 40%

o A lymphocyte count above 2,800 or below 1,800

o A blood protein level above 7.5 grams per 100 milliliters of serum

o A blood tryglyceride level above 150 mg percent ml

o A blood urea nitrogen (BUN) level above 18% or below 12%

o A level of nickel in the hair above 1.5 parts per million

o A hair mercury level above 1.5 ppm or below 0.4 ppm

o A hair aluminum level above 15 ppm

o A hair manganese level below 0.3 ppm

o Immune reactions to aluminum, nickel, mercury, copper or gold

o Oxyhemoglobin above 2.5% saturation

o T-lymphocytes that have been inactivated by mercury

o DNA analysis that indicates mercury-induced malignancies (doubled chromosome count)

Also, I will be posting a list of common symptoms on the Mercury Talk website soon and perhaps this will help. You may also want to find a doctor who specializes in heavy metal toxicity and testing if you can find one.

Best of luck and please keep us informed.