Tumor markers provide the possibility of early detection of tumors, and tumor marker testing is included in the medical examination program. However, when patients are faced with this tumor marker test sheet, they are still like reading from a heavenly book and cannot figure out the reason. There are more than 30 kinds of tumor markers, and about 10 kinds of tumor markers are commonly used in clinical practice, which can detect most common human tumors and cancers. However, the combination of multiple tumor markers can detect and diagnose tumors 3-5 years earlier than conventional tests (X-ray, MRI, B ultrasound, cytopathology), and can detect early tumors without symptoms, which can gain valuable time for treatment. It should be reminded that because of the non-specific nature of tumor markers, combined surveillance is usually performed. For example, CA199 is a sensitive marker for pancreatic and bile duct cancers, but combined with AFP and CEA is beneficial in diagnosing gastrointestinal tumors. NSE is the preferred marker for small cell lung cancer, but is usually monitored in combination with Cyfra21-1 to improve the diagnosis. When you see that your test result is higher than the reference value, do not be blindly alarmed because: 1. Tumor markers, as qualitative and quantitative indicators, often need continuous observation to reflect the nature of human biosignals more objectively. Therefore, if the indicators are elevated in normal asymptomatic physical examination population, they should be reexamined after one month or several times, or do corresponding further targeted examinations in order to get objective results; 2. Patients who are highly suspected of tumor should find a specialist to confirm the diagnosis; 3. Some inflammatory diseases cause transient elevation of corresponding indicators and should be followed up.