Better Solution for Duplicate Check?

[mykrobinson]

Morning, all! 

I'm working on internal testing for my hospital rounding app, and while most is working as it needs to, I came across an interesting (at least to me) problem this morning.

I couldn't think of much of a way to perform a test for duplicated patients when entering a new patient in the app, so i created a field call "duplicate check" with a formula to create the value in that field:

CONCATENATE(LOWER([Last Name]),LOWER([First Name]),[DOB])

 
For the validity check, i have this:

NOT(
	IN(
  	[_this],
    	SELECT(
      	Patients[_duplicatecheck],
        ([_THISROW].[_RowNumber]<>[_RowNumber]))))

The issue i am having is, I needed to edit a record this morning and append a middle name for a patient, as that information was not available in the information i initially had. It failed, though, and gave me the error message
A duplicate patient exists. Please verify the information entered.

How can I adjust my validity check to make sure that I can edit an existing patient and bypass the check?