This isn't possible yet. Health sensors are added automatically by PRTG. However, as of an update version of the initial release version (i.e. not the first release version) of version 12 it will be possible to add these sensor types manually. Please bear with us.
Disclaimer: The information in the Paessler Knowledge Base comes without warranty of any kind. Use at your own risk. Before applying any instructions please exercise proper system administrator housekeeping. You must make sure that a proper backup of all your data is available.