High calcitoninogen is a more specific marker of inflammation in bacterial infections and helps in the early diagnosis of bacterial infectious diseases. In contrast, calcitoninogen is often elevated briefly after major surgical procedures, followed by a gradual decline for 2 months. Non-infectious factors that cause elevated calcitoninogen are also systemic diseases, such as phagocytic syndrome, adult Still’s disease, etc.; and the acute phase of specific states, let’s say multiple injuries, major surgery and severe burns, early acute pancreatitis, subarachnoiditis, etc. In addition, it is seen in patients with tumors and transplants. A high calcitoninogen generally represents an infection, usually bacterial. If the calcitonin level is very high, above 2 or even higher, it is more likely to be a bacterial infection. Therefore, the combination of blood work, C-reactive protein, and calcitoninogen is often used to determine whether a patient has a bacterial or viral infection. Usually viral infections do not have a significant increase in calcitoninogen, but there are other diseases that can cause a high calcitoninogen, but none of them are as significant as bacterial infections or sepsis. Therefore, calcitoninogen is a very common test in hospitals, not only in infection departments, but also in routine blood tests and C-reactive protein. In many other departments, such as surgery, respiratory medicine, and connective tissue disease rheumatology, calcitoninogen may be checked frequently to rule out co-infections.