I did look into this back in September, because I did have a history of lead poisoning while in my mid 30's. I went to a doctor who specializes in occupational disease, which includes heavy metal poisoning.
I agree with Bob that blood tests are more reliable and would recommend going that route.
Audrey
I'd have a doctor draw blood for heavy metal testing. Hair is easy to contaminate and can pick up heavy metals from hair care products and the air. I biomedical engineering, I was exposed to all kinds of heavy metals and have never shown any levels above the norm. I guess if you were a heavy eater of shellfish or catfish from contaminated waters, it might be possible, but I'd have a medical blood test done to validate the hair test.
Bob