Well, to my knowledge, ICD standard was originally used for reimbursement purpose because ICD itself does not contain a specific detail about a disease. For example, in patient diagnosed with bacterial pneumonia, if we use ICD-10 for reimbursement, we will have to enter J159: Bacterial pneumonia, unspecified. As you can see, it tells us no more than what was this patient actually had, it does not tell us which lung was affected. In contrast, SNOMED-CT can tell us using a “concept”, that would be Pneumonia + Left/Right lung structure + gram positive bacteria
So, to answer the question, what if some hospitals in the country do not use ICD standard. Well, that would lead to reimbursement problem if the hospital were to pay a bill to the payee (Social security, insurance company or a government in CSMBS scheme) and they wouldn’t get paid. Even an ICD standard does not clarify the disease in detail, but at least, when sending a patient information about his/her diagnosis, it can still tell us what are the patients diagnosis.