Do you live in the SW USA? It is fairly common to see elevated U in the hair of such people.

Check out the 1000+ tests used by detox group members at this site.
http://livingnetwork.co.za/chelationnetwork/hairtest/hairtest3/

U is not as toxic as many people think.

I agree with you about the provoked urine test. Plenty of people regretted the decision to do it.
These are some comments in the archives of the yahoo detox groups
http://onibasu.com/wiki/Testing_for_mercury#Challenge_tests

Does the hair test have a strange, improbable patterns of essential elements such as almost all essential elements low or low norm, or 4 or more esential elements in the red or just too few elements in the green and white areas?

If so, check out Andy Cutler's theory on this subject. This is a discussion on an early version of his ' counting rules'.
http://onibasu.com/archives/am/2200.html

According to his theory, a test matching one of the rules is suspicious for mercury's effects on the movement--transport--of mercury in the body.

If a person also has a list of symptoms that are consistent with Hg toxicity, it then makes sense to consider Hg detox.

The details of "detox" is another subject. You'd be wise to do your homework before jumping in.

If you have liver problems including chemical sensitivities==MCS--consider the possible involvement of Hg, possibly plus arsenic. For example
http://howirecovered.com/meet-patti-who-recovered-from-mercury-poisoning/

Chlorella algae 1-2 grams at PM or PPM.

Spirulina at 3 grams and now foods 3771 will be required to keep mineral balance during chlorella chelation.

It could take a year to remove the heavy metal from the body, but it is natural removal, where available ions are removed. Japan and Russia have used it with success.

http://onlinepdf.co/radiation-detoxification-how-to-detoxify-your-body.html