Recently, there are consecutive netizens consulting about tumor markers, now we focus on answering the netizens on some of the most questionable issues for reference. 1.The test result is close to the upper limit of the reference value, is there any problem? For example, the test result of CEA is 4.8ug/L, and the reference value provided on the test sheet is 0-5ug/L. A: There is no problem. As long as the test result is within the reference value, it is normal. 2.Does a tumor marker test result out of the normal range necessarily mean that I have a tumor? A: Not necessarily, a tumor can never be diagnosed as a tumor simply because a tumor marker is higher than the normal range. However, if the tumor marker is higher than normal value, it should be taken seriously and further examination should be done. Especially when a certain indicator rises progressively. 3. What is the clinical role of tumor markers? The main role of tumor markers is to screen for tumors and to follow up the diagnosed tumor patients after treatment. 4.How is the normal value range of tumor markers determined? A: The reference value range of tumor markers is determined by the mean ± 1.96 times standard deviation (x ± 1.96s) of the measured values of certain indicators in a normal population. In fact, the normal value range of tumor markers does not include the measured values of all normal people, but only includes the measured values of 95% of normal people, that is to say, 5% of the normal people may have the results of the measured values of a certain index outside the normal value range. 5.How do some important tumor markers point to tumor sites? CEA — broad spectrum CA199 — pancreatic tumor, digestive system tumor CA125 — ovarian tumor, digestive system tumor AFP -liver tumors CA153 -breast tumors PSA -prostate tumors VCA-IgA- -nasopharyngeal tumors NSE – neuroendocrine tumors, small cell lung cancer