FUBAR as usual
If any of these apps are being used to assist with diagnosis or to direct treatment then they are medical devices and as such are required to have been developed to the ISO-13485 standard under the Medical Device Directives and have received a CE mark.
If they have not received a CE mark, then it is a criminal offence to use them in a clinical context.
https://www.bsigroup.com/en-GB/medical-devices/our-services/iso-13485/
