Is there any guidance provided as to how many of the supplied query criteria should be used when responding to a 270? For example, should the application validate the ID, last name, first name, and DOB or can it stop as soon as it finds a unique match (i.e. ID matches one and only one member)? If it stops there, should it also validate that the one and only match also matches the last name, first name and DOB as supplied?
This issue is explicitly addressed in guide X279 in section 1.4.8.1, which states "When the patient is the subscriber, it is recommended that an Information Source use all four of these elements in locating the patient in their database; however Information Receivers should be aware that the Information Source might not have used all four of these elements."
Therefore, the health plan is not required to use all of the information received. Once they identify the specific patient, they can craft the response.
Section 1.4.7.1 also 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 reported in the 271 is what is needed for the eventual claim submission.