In the class DV_ORDERED, there is a set of reference ranges each of whose
purpose is identified by a DV_TEXT. If there are any ranges at all, one of
these is usually labelled "normal". The problem with this is that it is too
unreliable, and also language-dependent, yet there is a very strong
requirement to be able to find unequivocally the normal range (and
most frequently, it is the only one, as with most path results).