Dealing with Duplicate Data

Hi,
I have a client that wants to setup a data entry form the has the following info:
- Last Name
- First Name
- Date of Birth
- Type of Test (with a pull down of five test options)

He wants to enter the submitted info into a google sheet BUT he wants to prevent duplicate data on the test type. If the person has had the test conducted before the system needs to go to an error page stating that the user cannot be added to the sheet or it needs to put an error when submission is attempted notifying the staff member about this. Can your system do this?

Duplicate submissions can be prevented with Unique Submission and Unique Question features. 

How to Set Unique Submissions on a Form

How to set Form Limits Based on a Unique Question

How to Have Unique Question Using Multiple Fields