Hi, Thanks for posting in HCM. I understand your concern. Carcinoembryonic antigen (CEA) test measures the level of CEA in the blood. CEA is a protein normally found in the tissue of a developing baby in the womb. The blood level of this protein disappears or becomes very low after birth. In adults, an abnormal level of CEA is a tumor marker and may indicate the presence of cancer, especially cancers of the large intestine and rectum. Smoking, infection and inflammatory bowel disease may increase and alter the CEA levels. Other cancer where its levels are increased include: medullary thyroid carcinoma, breast cancer, liver cancer, lung cancer, ovarian cancer, pancreatic cancer and prostate cancer. Normal level of CEA is less than or equal to 3 ng/mL. Most healthy people have levels below this amount. Since it is only a tumor marker, these cancer needs to be evaluated by means of other investigations to confirm the diagnosis. Since your levels are fluctuating, it certainly needs evaluation and is advisable for you to consult Oncologist to review the same. Hope the information provided would be helpful. All the best.