Hi Mother,
Yes I've had two done (with Trace Elements Inc) both revealing mercury toxicity, more apparent in the first where mercury did show up at an unacceptable level. Both tests revealed very skewed/deranged minerals eg very low potassium and low sodium, and other lows.
About hair testing in general I would just reiterate what Johnny said....mercury doesn't HAVE to show up. They should be interpreted properly. Alongside looking at symptoms and history they are a *very* useful tool for determining mercury toxicity and other health issues like metabolic/thyroid and adrenal problems which mercury contributes to.
You stay strong too :)
Anne