App idea where a user goes and has testing done and the testing agency conditionally releases the information electronically. A user can give a code to another party to allow them access to the test results.
The example that I was first thinking of was for dating. Someone who is considering a liaison might be favorably inclined if their potential partner could show them a recent clean bill of sexual health. If doing so meant a simple exchange between smart phones.
The legally tricky part would be the laws surrounding release of medical records. Some cryptographic function would have to be considered equivalent to a signature.
I suppose though that would simply be in the contract the user signs when getting the procedure done.