In test due screen the last test date for any test should not be updated until unless it is performed with data..

For X-Ray:- No last test date update in Test due screen until x-ray result is selected normal/abnormal.
For PFT:- No last test date update in Test due screen until IsDone is not ticked.
For Audiometry:- No last test date update in Test due screen until any IsDone is not ticked.