A squamous epithelial cell carcinoma antigen test value of 3.05 suggests possible cancerous lesions such as lung, cervical, or esophageal cancer or cancer recurrence. However, a diagnosis is needed before treating the cause. Squamous epithelial cell carcinoma antigen can be used as one of the markers for the auxiliary diagnosis of tumors, evaluation of the efficacy of treatment, monitoring of recurrence, and assessment of prognosis, and the normal range is <1.5 μg/L. The elevated level of squamous epithelial cell carcinoma antigen in serum may be caused by squamous cell carcinoma of the lung, esophageal cancer, cervical cancer and other diseases, and patients need to combine with lung CT, esophageal microscopy, abdominal CT, pathological biopsy and other examinations to make a clear diagnosis. In addition to tumor, serious infection, inflammation or autoimmune disease in active stage can also cause elevated level of squamous epithelial cell carcinoma antigen in the body. Patients who are found to have elevated levels of squamous epithelial cell carcinoma antigen should be diagnosed as soon as possible. If the diagnosis is malignant tumor, surgery, radiotherapy and chemotherapy should be chosen in time to avoid delaying the condition.