Testing a single orifice in an NIST certified hydraulic lab is a waste of time and money in most cases. The performance of the orifice plate will be determined based upon the lab piping into which it is installed and tested. When the orifice is subsequently installed in the field, it is rare that the piping would match that of the testing facility.
The orifice plate represents one component of the primary flow element assembly. The other components are the meter tappings (ie. flange, corner, radius, pipe) and the required up and downstream controlled ID piping.
The complete assembly should be supplied from a reputable meter manufacturer and forwarded to the testing facility for performance evaluation.
Hope this helps.
bk