Carcino Embryonic Antigen

The Carcino Embryonic Antigen or CEA test is used to measure the level of CEA, a protein that can be present in higher amounts in certain types of cancers, particularly the adenocarcinoma of the large intestine and rectum (colorectal cancers). However, it may also be used to monitor other cancers, such as breast, lung, thyroid, and pancreatic cancer.

Carcinogenic embryonic antigen (CEA) is a protein typically produced during fetal development but is present at very low levels in healthy adults. Higher CEA levels can indicate the presence of certain types of cancer, but non-cancerous conditions, such as inflammation, smoking, infections, and disorders such as inflammatory bowel disease, pancreatitis, cirrhosis of the liver, and some benign tumors can also influence them.

Your doctor may recommend the Carcino Embryonic Antigen test to monitor if cancer has spread to other body regions (metastasized), determine the treatment response, and check for recurrence. The test is typically meant for individuals with symptoms suggestive of colorectal cancer, like sudden weight loss, changes in bowel habits, or abdominal pain, or for those with a history of colorectal cancer or other cancers. However, the test is not recommended for routine cancer screening in asymptomatic individuals (healthy or those without any suggestive symptoms).

It is important to note that the Carcino Embryonic Antigen test is not a standalone test; other confirmatory procedures, such as imaging studies or biopsies, are often necessary to validate cancer diagnosis. Higher than normal CEA levels may suggest the presence of cancer or other conditions. However, false positives (denoting the presence of cancer when cancer is absent) and false negatives (denoting the absence of cancer when cancer is present) can also occur. Additionally, sometimes, patients with confirmed cancer (by imaging, etc.) may have normal CEA levels. It is, therefore, advised to go for repeat/serial testing to look for consistently raised CEA levels. 

CEA levels generally return to normal between one and four months after the cancer has been successfully removed. Hence, baseline CEA levels are established before starting treatment for meaningful evaluation of treatment response, and detecting recurrences as persistently high levels after therapy or during follow-up may raise suspicion of ineffective treatment or recurrence.

Usually, no special preparation is needed before undergoing the Carcino Embryonic Antigen test. However, providing a brief clinical history/doctor's prescription at the time of sample collection is important. CEA samples should preferably be collected before colonoscopy as the procedure may temporarily raise tumor marker levels. Additionally, tell your doctor about any medications and supplements you take, as certain medications can affect your test results.

Reference ranges are approximate and may vary based on age, gender, medical history, etc. Values obtained with different assay methodologies should not be used interchangeably in serial testing. It is recommended that only one assay method be used consistently to monitor each patient's course of therapy. Abnormal test results require an expert interpretation; therefore, never try to self-medicate at home based solely on these results, and always consult a doctor for a proper understanding of the test results.