For what its worth, I have to respectfully disagree with you Kurt on the "sign" versus "symptom" point...
"...Patient states he only drank one drink today..." -- symptom
"...but is weaving and slurring his words..." -- sign
"...His BAC is .20..." -- sign
My understanding is that the defining difference is that symptoms are reported by the patient, ("...I feel this... I experience this...") -- there is an experiential element to them -- whereas signs are not, ("...patient displays indications...", "...is clearly limping..."). Another way to look at it is to ask where does the perception occur? Who perceives the indication, the patient or the doctor?
I don't think too many people have walked into a doctor's office and said, "I am in denial about my drinking". By definition, denial is not perceived by the patient and therefore can not be a symptom. It can however, be perceived and inferred by someone who is not the patient, such as a doctor, therefore making it a sign.
My understanding is also that neither a sign nor a symptom need to be quantifiable in order to be valid. They can also be qualitative in nature... "I feel like crap" or "general malaise" are both perfectly valid symptoms, just as "exhibits poor motor control" is a perfectly valid sign. They do not need to be measured in order to be observed.
Just my two cents... Sorry if I'm off topic.