An orifice plate carrier for an orifice plate fitting is disclosed in which the downstream surface of the carrier has a radial lip partially occluded the orifice plate opening. The lip is configured to define the axial position of the orifice plate in the carrier and to also establish a seal between the lip and the orifice plate seal member. An orifice plate carrier also may comprise an orifice plate insert configured to allow a single carrier to accept multiple orifice plate members. An insert may be configured to accept a first type of orifice seal member, but not a second type.