" A physician may order the quantitation of a marker such as CEA in a patient suspected of having cancer. Carcinoembryonic antigen has a normal range of approximately 0 to 10 ug/L in most patients, but is not considered a good screening test since it may be elevated above 10 ug/L because of any one of a variety of other conditions, such as smoking, alcoholic cirrhosis, inflammatory bowel or chronic pulmonary disease. Thus, although a value of 15 ug/L would be above the reference interval established for a healthy, nonsmoking population, such a value could reflect a patient with an underlying chronic condition in the liver, intestine or lung, instead of the presence of cancer. " According to the passage which value of CEA may not indicate the presence of cancer? ( )