High ferritin may not necessarily be cancer, but may also be caused by benign diseases. Measurement of serum ferritin concentration can be used clinically as an auxiliary diagnosis of malignant tumors. The ferritin concentration in the blood of many patients with malignant tumors may be significantly elevated, but the detection of ferritin concentration is affected by many factors, such as machine detection bias and specimens left for too long, which can affect the test results. In addition, many benign diseases can also lead to increased ferritin concentrations, such as infectious diseases, autoimmune diseases, including rheumatoid arthritis and diabetes. Patients with long-term recurrent blood transfusions can also develop increased concentrations of blood ferritin, known as hemochromatosis. Therefore, an increased concentration of serum ferritin cannot necessarily mean cancer. Firstly, we should pay attention to the review, and secondly, we should combine with other examinations for final confirmation.