If the 270 is sent out with the patient being the subscriber in the 2100C loop, and the payer determines that the patient is a dependent, I believe the 271 will be returned with the 2100C having the correct subscriber information, and the patient will then be returned in the 2100D loop. Under this circumstance, what is in the INS? According to how I am reading this segment's use, INS01 and INS02 are required elements when the segment is sent, and INS02 may only be '18' for SELF. Since INS02 may only be 'SELF', I don't see how the 2100C INS is returned when there is a change as noted above. What tells the provider that the patient is not the Subscriber, and the 271 has the correct subscriber data? Just the fact that the 2100D loop was sent on the 271 when only the 2100C was on the 270? Or is the INS to be used differently than I am interpreting?
It is not necessary to return an INS01 or INS02 in the 2100C loop to identify the dependent was moved from the 2100C loop on the request to the 2100D loop on the response.
In 005010X279, it is not required that an INS segment be returned when identifying elements have changed on the 271 response from that submitted on the 270 inquiry. If the information source chooses to acknowledge that a change in indentifying elements has occurred between the 270 and the 271, they would do so using INS03 and INS04. INS01 and INS02 would not indicate a change has occurred.
Please note, Section 1.4.7.1 states "...any other information (e.g. Address) required to identify the individual on subsequent EDI transactions (e.g. 837 Health Care Claim or 278 Health Care Services Review - Request for Review) must be returned". Therefore the health plan must be certain that the information is reported at the correct loop level in the 271 to properly allow for how it would be required to be submitted for the eventual Claim Encounter or Request for Review transactions.