The normal range for cytokeratin 19 fragment is <3.3 ng/ml, and 4.8 ng/ml is higher than normal, but the elevation is not significant. Cytokeratin 19 fragment is a tumor marker for squamous cell carcinoma of the lung and can be elevated in cervical, bladder, and prostate cancers. Mild elevation of cytokeratin 19 fragment is also seen in many benign diseases, such as pneumonia, peptic ulcer and chronic bronchitis. Therefore, cytokeratin 19 fragment 4.8ng/ml, mildly elevated does not mean that there is a tumor, but also need to be combined with other tumor markers, such as carcinoembryonic antigen, squamous cell carcinoma-related antigen assay, gastrin-releasing peptide precursor, etc., and also need to be combined with imaging, such as CT examination, magnetic examination, etc., and the final diagnosis needs to be confirmed by biopsy to obtain pathology. Cytokeratin 19 fragment results of 4.8ng/ml, it is recommended to go to the hospital, follow the doctor's instructions for relevant examinations, targeted treatment.