Methods, apparatuses, computer program products, devices and systems are described that carry out implementing in at least one device at least one user-health test function that is structurally distinct from at least one application whose primary function is different from symptom detection, the at least one application being operable on the at least one device; obtaining user data in response to an interaction between a user and the at least one application; and presenting an output of the at least one user-health test function at least partly based on the user data.