An eGFR blood test is used whenever there is suspicion of a kidney disease. This is usually the case in patients who are suffering from diabetes or from hypertension for a prolonged period of time.
In the case that your APP file doesn't open, it is highly likely that you do not have the correct software application installed on your PC to view or edit APP file extensions. If your PC opens the APP file, but it's the wrong application, you'll need to change your Windows registry file association settings. In other words, Windows is associating APP file extensions with the wrong software program.
In order to be opened, a file needs an application that is compatible with its data. When you open a file on your Mac, the application that reads the file is also opened on your computer. A file will remain open until you close it or shut down your computer.