I can see requiring lab coats (or better, rubber aprons) to protect clothing
from stains and the person underneath from solvents and other reagents.  (My
research lab frequently uses trichloroacetic acid.)  I see no objection to
jeans, which have become standard collage wear.  Patients and their visitors
really don't belong in the path lab.
    I disagree with Donald Anderson's opinion that the clothes make the man.
It is the man (or woman) who imparts meaning to the clothes.  The uniform of
one of our local schools has come to stand for thuggery because that's the
way its students behave.