We check by name and match birthdates (where are multiple names the same). Pick up an aamazing number of duplicate MRN's. Once we have a name and birthdate match, we match the SSN. We have to do this,e ven beyond the duplicate MRN issue, because we are a 5 hospital system with 2 of them using different MRN's. I don't think the duplicate problem is going to go away anytime soon, esp since pts give differing info many times. Sometimes they give a middle name, sometimes use maiden name as middle initial and who knows what else. Good luck, we all just do the best we can.