What kind of specialist does one need to see in order to have an overall health check, including organ functionality, cholesterol etc?

Not a specialist: Specialists do not do overall health checks because specialists focus on one bodily system or one part of the body. Primary care doctors focus on overall health, without the specialty bias that a patient would get if he or she were to get an overall health check at a specialty clinic. A primary care doctor is trained in helping patients achieve and continue good physical and psychological health.