In looking at Structured Numeric in v2, it allows for the following comparators
>
<
>=
<=
=
<>

In FHIR there are only the first 4 on observation.valueQuantity, http://build.fhir.org/valueset-quantity-comparator.html and an "ad" which I don't think has a match.. One could conclude that = is just a value without a comparator but how do we handle the not equal (<>) value in FHIR.

We note that we have never seen that result in a lab test but there may be other observation types that need it. So the options of my request are
a) remove from SN definition or
b) add to FHIR Quantity comparator or
c) define another way to represent it in FHIR