The normal value of carcinoembryonic antigen is about 5 ng/ml or less. If the test is more than four times the normal value, that is, if the test is 20 ng/ml, there is a high probability of cancer, but this is not absolute and further tests are needed to confirm.
If the carcinoembryonic antigen rises very rapidly and continues to rise, there is a high probability of cancer, such as lung cancer, stomach cancer, and so on. If the test is more than 10 times the normal value, it is possible to confirm cancer or a malignant tumor.