Cancer is a generic term for a large group of diseases that can occur in various parts of the body. The diagnosis of cancer may not be fully evident by blood tests alone. Of course, there are some tumor markers that may be elevated in cancer, but they have to be combined with other imaging tests and further pathological examinations to fully confirm the diagnosis. Blood test is only a preliminary screening tool, but of course it depends on what kind of blood is tested. If the blood test is only for routine blood, liver function and kidney function, there is no way to detect cancer. If it is a tumor marker test, it may be more helpful to diagnose cancer. For example, if the index of AFP is elevated more, combined with the imaging examination, it is possible to make a clinical diagnosis of liver cancer, but the diagnosis depends on liver aspiration or post-surgical pathology.