Could a sed rate be elevated with mercury poisoning from too much tuna (eating a can of tuna everyday for years?) other symptoms: weak & can't walk.

Unlikely: Do you really have mercury poisoning from eating canned tuna? May be a need to contact the epa if this is correct. You could very well possess a peripheral neuropathy, but is your problem localized there or is there a spinal cord issue instead? Sed rate is not usually a marker of poisoning, and may be indicative of a vasculitis or even diabetes. Is your diagnosis truly confirmed?