Cancer markers falling outside the normal range need not be a cause for concern as there could be other reasons for the elevated levels of the markers. One prominent reason is the presence of a disease or health condition other than cancer, says Cancer.Net.
The National Cancer Institute states that it is possible that even individuals without cancer show cancer marker test results outside the normal range. That is because, apart from cancer cells, these markers are also produced by the healthy cells in the body, says Cancer.Net.
Also, the tumor marker levels tend to vary with time, indeed from month to month, reports Cancer.Net. This makes it quite difficult to obtain consistent results. Doctors usually recommend serial testing and compare the results of multiple tests to determine the presence of cancer, states National Cancer Institute.
It is also possible that in people with cancer, the cancer marker level falls within the normal range. This makes the tumor marker tests alone quite unreliable for diagnosing cancer, which is why doctors recommend a biopsy to confirm cancer diagnosis. The overall health status of the patient, medical history and the results of other tests and examinations are also taken into consideration when making a cancer diagnosis, explains National Cancer Institute.