There have been clinical decision support systems around for years which can recommend a diagnosis given complete and accurate clinical data. The real problem is gathering that data, and putting it in a form that the algorithm can use. An AI algorithm can't really gather a detailed patient history or make subjective observations about the patient's state. Those are steps which can't really be automated without strong AGI. In theory a doctor could do all the necessary data entry but in practice it would usually be a waste of time and no one wants to pay for it.