Non-small cell lung cancer antigen 4.29ng/ml is higher than normal, but not very high and is mildly elevated. The highest specificity of NSCLC antigen is cytokeratin 19 fragment or CYFRA21-1, which is important for the diagnosis of NSCLC, so the NSCLC antigen mentioned here should refer to cytokeratin 19 fragment. Cytokeratin 19 fragments are found mainly in epithelial-rich tissues such as the uterus, lungs, and intestines, and are elevated when lesions occur in these organs. Non-small cell lung cancer antigen should be <3.3ng/m. Elevated cytokeratin 19 fragment is commonly found in benign diseases such as pneumonia, tuberculosis, cystitis, mastitis, etc., and most of them are mildly elevated, not more than 10ng/ml; it can also be seen in malignant tumors such as non-small cell lung cancer, bladder cancer, colorectal cancer and breast cancer. Non-small cell lung cancer antigen 4.29ng/ml is higher than the normal value, which is mildly elevated, most likely caused by benign diseases, but does not exclude the possibility of malignant tumors. It is recommended that the patient consult a specialist, combine with other test results to make a comprehensive judgment, and further examination and treatment if necessary.