Non-small cell lung cancer-associated antigen 3.6ng/ml is higher than normal and is usually not very serious if caused by benign disease, but serious if caused by malignant tumor. Cytokeratin 19 fragment (CYFRA21-1) is the preferred tumor marker for non-small cell lung cancer, also known as non-small cell lung cancer-associated antigen.Elevated CYFRA21-1 can be seen in malignant tumors, such as lung, breast, and bladder cancers, as well as in benign diseases, such as pneumonia, tuberculosis, and chronic bronchitis. A CYFRA21-1 value of 3.6ng/ml is considered mildly elevated, and benign diseases are more likely to improve or recover with timely treatment. CYFRA21-1 value of 3.6ng/ml does not exclude the possibility of malignant tumors, which is a serious situation and requires early treatment. It is recommended that the patient should consult the doctor in time, so as to avoid delaying the disease.