Drawing blood for tumor marker is more accurate for determining the five indicators of lung cancer, if blood is drawn for routine blood test, while the five indicators of lung cancer cannot be checked. In addition, patients also need to do chest X-ray, chest CT and other tests to assist in diagnosing lung cancer. If blood is drawn to test carcinoembryonic antigen, squamous cell carcinoma antigen, neurospecific enolase, gastrin-releasing peptide precursor, cytokeratin 19 fragment antigen and other tumor markers of lung cancer, patients undergo tumor marker penta-examination, which is of certain reference value for diagnosing lung cancer, so it is more accurate to do tumor marker penta-examination by drawing blood. If blood tests such as routine blood tests are taken, lung cancer cannot be detected in general. It is suggested that lung cancer patients also need to take chest X-ray, chest CT, bronchoscopy, cytology examination, which is helpful to determine whether lung cancer is present. For patients suspected of lung cancer, they need to go to the hospital in time to have blood drawn for tumor marker tests, and at the same time, they also need to take other tests such as thoracoscopy and chest MRI.