what is a high cea level

A high CEA level indicates that there may be an underlying medical condition, including cancer, but it is not a definitive marker of a particular site of cancer origin. CEA stands for carcinoembryonic antigen, which is a protein that is a type of "tumor marker". Tumor markers are substances that are often made by cancer cells or by normal cells in response to cancer. High levels of CEA are normal in healthy, unborn babies, but after birth, CEA levels become very low or disappear completely. In healthy, non-smoking adults, CEA is considered within normal limits at a level of 0-2.9 ng/mL of blood. Smokers may have elevated CEA, and therefore it is considered within normal limits at a level of <5 µg/L. A low level of CEA may mean that the tumor is small and the cancer has not spread to other parts of the body, while a high level of CEA may mean that the tumor is large or has spread to other parts of the body. However, a higher than normal level of CEA alone cannot diagnose a new cancer, and further testing is needed. CEA tests are not used to screen for or diagnose cancer, but they are used to monitor the progress of certain treatments.