Why medical history of the patients has not maintained globally on a common software?

This is because not every country is given the financial means to operate their healthcare system in an orderly and modern way. It is true that it would make it a lot easier not only for healthcare workers but also for the patients' because they will no longer have to wait in line for interview of medical history and so on.And so, in as much as every other country in the world would like to have a modernized healthcare system, it all goes down to their financial ability and the amount of support the government is willing to give to the healthcare industry.

In the  modern world each nations has different protocol to maintain the patients confidential documents of medical history.so ,each countries  has not propose the common software for medical history of a patient. although ,common software will be a helpful in-terms of migration from one country to another or during visiting visa to get details of patient immediadtely.