nse is an acidic protease that is a specific marker for neuroendocrine tumors and one of the important markers for small cell lung cancer. The normal value of serum nse should be less than 12.5 U/ml. A higher than normal test result may be related to small cell lung cancer, theoblastoma, pheochromocytoma, etc. If it is mildly high, there is no need to worry excessively because benign lung diseases, cerebrospinal meningitis, cerebral infarction, traumatic brain injury, etc. may also lead to mild elevation. If the elevation is larger, further examination should be conducted at regular hospitals to clarify the diagnosis, then formulate treatment methods and conduct regular monitoring and review.