An elevated cyfra21-1 of 4.0 μg/L suggests that there may be a risk of malignancy present, but elevated levels of this indicator are also present in certain benign diseases. Elevated cyfra21-1 (cytokeratin 19 fragment) is a soluble fragment of keratin CK19, which can be detected after being secreted into the bloodstream. cyfra21-1 can also be seen in benign diseases, such as pneumonia, tuberculosis, chronic bronchitis, gastrointestinal diseases, gynecological diseases, and urinary system diseases. If you feel unwell, seek medical attention. For specific cases, it is recommended that you consult a specialist for a full review and evaluation.