CEA Test: Full Form, Normal Range and What High Levels Mean

CEA full form is Carcinoembryonic Antigen. The CEA test is a blood test that measures the protein in the blood. The test is normally ordered by doctors to measure how the patient reacts to cancer or its treatment, especially colon or rectum cancer.

It should be noted that the abnormal results do not always indicate cancer since there are other factors which may affect the increased levels of CEA such as smoking, liver diseases, and inflammatory processes. It is possible for the person to have normal test results in case of cancer since not all the tumors produce CEA.

Information about the normal values of CEA test, the causes of raised test results and the reasons for regular testing will help patients understand their results better. This blog will help you to learn what the CEA test is, when it is needed, how it is evaluated and what additional tests may be required.

What Is a CEA Test and What Does It Measure?

Carcinoembryonic Antigen (CEA) is a glycoprotein naturally occurring during fetal development and which levels become very low after birth. Some types of cancer cells are able to produce larger quantities of this protein, hence it is used as a tumor biomarker diagnosis particularly in certain types of cancer.

This test detects the quantity of CEA in the blood and its unit is usually nanogram per milliliter (ng/mL). While high levels of CEA can be seen in some cancers like colon cancer, it can also happen due to non-cancerous conditions. It therefore cannot be used alone to detect cancer but helps in monitoring therapy among others.

Why Do Doctors Recommend a CEA Blood Test?

The CEA test can be done before, during or after cancer treatment. This depends on the specific diagnosis of the patient as well as the information needed.

Before commencing treatment

A baseline test of the CEA levels will help to know how these levels change during the course of treatment. It helps doctors to compare results later. CEA is not used on its own to diagnose cancer.

During chemotherapy or radiation therapy

Repetition of tests might be helpful in assessing any change in the levels of CEA during treatment, whereby a reduction of levels would be an indication of positive response to treatment.

Disease progression assessment

CEA levels can give additional data regarding disease activity in certain cancer patients who have advanced stages of their disease. This data is considered by doctors in conjunction with signs, physical examination results and imaging findings. However, the test is not needed in all cancer cases. The test is useful only for cancers that release CEA.

The CEA test may be done as part of follow up. However, if CEA levels begin to increase when they were previously decreasing, further tests may be necessary.

What Is the Normal CEA Test Range?

The normal range is the level usually seen in healthy people. However, there may be some variations in the reference values in different labs as a result of differences in equipment used for the tests. According to Mayo Clinic Laboratories, the reference values for CEA test in serum are as follows:

For non-smokers - 3.0 ng/mL or lower.

For some smokers – usually lower than 5.0 ng/mL.

How Should You Understand Your CEA Report?

The interpretation of CEA test results involves checking the levels against the reference range of the particular laboratory. Your result can fall into one of two groups:

CEA within Reference Range: When the outcome is within the reference range, it implies that the CEA levels are not high. However, even if the levels are normal, they do not necessarily exclude the possibility of having cancer.

High CEA Levels: Results which are above the reference range indicate that the levels of CEA are high. Further tests will be recommended based on the patient’s health conditions.

For patients who have had colorectal cancer screening in the past, the CEA levels will be compared to previous results. It is necessary to take into account the fact that different laboratories use different methods and references. Hence, the patients should not compare their results to the values provided online.

What Does a High CEA Level Mean?

High CEA levels mean that the concentration detected is above the range set by the laboratory. This can be interpreted differently according to the patient's medical history and their present condition.

In patients who are under cancer therapy, higher CEA levels can imply changes in the course of their illness. In case CEA levels begin to increase after falling during therapy, additional tests may be recommended to detect cancer recurrence or development.

A high CEA level alone cannot show tumour size, location or stage. Doctors also look at:

CEA Level: The amount by which the test result is above the laboratory reference range.

Previous Test Results: If CEA levels remain constant, drop or rise over time.

Treatment History: If the patient had any surgery, chemotherapy or radiotherapy.

Other Medical Findings: If any symptoms, physical exam or diagnostic imaging shows any changes in the disease condition.

In some cases, an abnormal test result might be transient and doctors may conduct another CEA Test or further tests before arriving at any diagnosis.

Important Note: An elevated level of CEA does not necessarily mean that cancer is advancing. It has to be considered in relation to other criteria.

Can High CEA Levels Occur Without Cancer?

Many health conditions that are non-cancerous will contribute towards elevating CEA levels. It is essential to take into account these conditions since the marker is not specific to cancer only. For instance,

Smoking: Those individuals exposed to tobacco will record increased CEA levels. Those individuals who are smokers may show increased results compared to those who do not smoke, affecting the interpretation of their test results.

Liver conditions: The liver contributes towards metabolic processes in the blood. Some conditions like cirrhosis and others might result in increased CEA levels.

Inflammatory bowel diseases: Conditions like Crohn’s disease and ulcerative colitis create inflammation of the digestive system. Sometimes in such cases, these conditions can raise CEA levels.

Gastrointestinal diseases: These include conditions like gastritis, ulcers in the stomach, and diverticulitis.

Respiratory diseases: Some types of chronic obstructive pulmonary disease (COPD), along with some other respiratory diseases, may cause increased CEA levels.

Other diseases: Some other conditions, such as pancreatitis and an underactive thyroid, can also raise CEA.

The occurrence of such factors alone does not explain all the abnormal results. The physician will evaluate the symptoms and history of the patient along with the results in order to determine the probable cause. That is the reason why the result of a CEA test should be consulted with a doctor instead of considering it as evidence of a disease.

Which Cancers Can Cause Elevated CEA Levels?

CEA is elevated in various types of cancer; however, the levels may vary among individuals, such that while some tumours will secrete large amounts of CEA, others will not. Cancers that are related to elevated CEA levels are:

Colorectal cancer: Cancer in the colon or the rectum is one of the most well-known contexts where CEA measurement can be performed clinically. Repeat testing could be done to monitor response to treatment and check for any recurrence.

Lung cancer: Lung cancer is another type of cancer, which in some cases can lead to elevated CEA levels. CEA could be used as an additional marker in certain individuals.

Breast cancer: There are individuals with breast cancer, who might exhibit elevated CEA levels. This test result could be interpreted together with other clinical tests.

Pancreatic cancer: Patients with pancreatic cancer may show increased CEA levels. However, CEA is not specific enough to diagnose this condition.

Stomach cancer: CEA may be used along with other tests.

Other cancers: Abnormal results have also been observed in patients suffering from ovarian, liver and medullary thyroid cancers.

The existence of such associations does not necessarily imply that all people with such cancers will have elevated CEA levels. It depends on the type of cancer and the purpose of the test.

What Is the Role of CEA Testing in Colorectal Cancer?

The CEA test for colorectal cancer is useful in tracking certain patients, especially those that have tumors secreting this protein. The CEA test adds more knowledge during treatment and post-treatment, but is not used as a substitute for imaging and other tests.

Baseline Level Before Treatment

Physicians may conduct the CEA test before treatment to get the patient's baseline level of CEA. The result serves as a standard when making comparisons in the future. If the tumour releases CEA, the baseline helps doctors track it during and after treatment.

Treatment Monitoring

While undergoing chemotherapy or other therapies prescribed by the physician, the test will be conducted again to evaluate the change in the marker. Consistently reducing levels can indicate the efficacy of treatment. However, a reduced level does not mean a definite indication that the cancer has gone away, and imaging and physical examinations need to be performed.

Colorectal Cancer Treatment Follow-Up Tests

In case of colorectal cancer surgery, CEA will also be included in the follow-up testing. This can show the need for further tests.. An increased level or increasing values after previous reduction can also suggest the necessity of additional research.

Examining Possible Cancer Recurrence

The term “cancer recurrence” describes the situation where cancer returns after its treatment. If the levels of CEA rise continuously in cases of colorectal cancer, it might suggest cancer recurrence, especially if the patient already had a high level of CEA. To find out the cause of this, the physician may order imaging studies or a colonoscopy.

How Is the CEA Test Performed and How Should You Prepare?

The CEA blood test is commonly a relatively simple lab test. This process is very quick and involves obtaining a small amount of blood from the vein. Process of Taking CEA Blood Test:

Preparation: The health care provider cleans the skin surface, especially the inner side of the arm.

Obtaining blood: A small needle is used to withdraw blood samples.

Laboratory tests: The sample is analyzed in the laboratory for CEA levels.

Results: The lab reports your CEA value with its reference range.

There may be some stinging or bruising sensation among certain patients on needle prick. However, these are normal and should go away without any treatment.

Is Fasting Required Before the CEA Test?

Fasting is usually not needed for an ordinary CEA blood test. However, patients are recommended to follow the guidelines issued by their physician or diagnostic center.

However, individuals who smoke need to inform their healthcare provider about this factor since smoking can affect the outcome. Also, patients are advised to share other health problems and medications when talking about their results.

If CEA is tested in a body fluid other than blood, then the procedure might vary. Special guidelines for this kind of procedure will be provided to the patient.

What Happens If Your CEA Test Result Is Abnormal?

A high level of CEA does not always indicate the presence of cancer. Firstly, the result is interpreted taking into account the previous levels and treatment received. The patient may undergo one of the following:

Repetition of blood testing: This can help assess if the increase was temporary or not.

Review of the medical history: Questions regarding smoking habits, prior treatments for cancer, liver diseases, and digestive problems may be raised.

Imaging tests: These include CT scans or MRI if there is a need for examining a particular part.

Colonoscopy: In case colorectal cancer has recurred or there are other bowel problems that have developed, colonoscopy can be used to view the inside lining of the colon and rectum. A biopsy is taken if an unusual area is found.

Other laboratory tests: More blood tests could be ordered to determine whether there are issues with liver functions or other health problems.

Not all patients need all these tests. This is determined by the particular diagnosis and symptoms. However, patients must not discontinue their cancer treatments based on any one abnormal result obtained.

When Should You Consult a Doctor?

You should consult a healthcare professional if the CEA test result exceeds the reference values of the laboratory or indicates an upward trend relative to past results. The consultation becomes especially urgent if you have ever had cancer and are undergoing follow-up after it. Symptoms, for which you need to seek medical advice, include:

• Unexplained weight loss or chronic fatigue.
• Changes in bowel activity that do not go away.
• Presence of blood in feces.
• Chronic pain in the abdomen.
• Loss of appetite without any cause.

These symptoms may not be related to cancer, but it is important to address them and undergo examination by a physician if necessary.

Consult Today

The interpretation of an abnormal CEA test can be difficult especially among people who are under cancer treatment. It will be useful to seek advice from an oncologist to get an idea of what it means and whether further tests are necessary.

If you have questions about your diagnostic tests or cancer treatments, at Oncare Cancer Hospital you will get professional advice from an oncology specialist. We can guide you through your cancer treatment with our knowledge and experience. Contact Oncare and get started with your cancer treatment today.

Medical Disclaimer

The information provided in this article is meant for education and should not substitute for any professional medical advice. CEA levels on their own cannot diagnose or exclude the presence of cancer. There may be differences between reference values used by laboratories, and test results need to be interpreted together with the rest of the patient’s medical profile and investigations. Consult your doctor for further information.