General Health

Which Laboratory Tests are Used to Diagnose Cancer?


The level of carcinoembryonic antigen (CEA) in the blood or other body fluids is measured by a CEA test. CEA is a form of tumour marker that determines whether cancer is developing and spreading or diminishing in therapeutic response. CEA assay, CEA blood test, and carcinoembryonic antigen test are all titles for the same investigation which is the CEA test. Individuals can be tested for CEA before starting treatment, throughout treatment, or after concluding treatment.

A prenatal child produces CEA while in the uterus, however, healthy adults make little or none of this protein. Smokers, as well as those with the following noncancerous diseases, may have elevated levels of carcinoembryonic antigen:

  • If the gallbladder is inflamed (cholecystitis)
  • Cirrhosis
  • Breast conditions that are benign (non-cancerous) affect the majority of women. The majority of breast variations are benign. Benign breast diseases, unlike breast malignancies, are not life-threatening. However, some have been linked to a higher risk of breast cancer in the future.
  • The pancreas is inflamed (pancreatitis)
  • A stomach ulcer
  • Colitis ulcerative
  • Polyps, A polyp is a small protrusion of unwanted tissue on the lining of the large intestine, often referred to as the colon. Colon and rectal polyps affect roughly 25% of men and women over the age of 50. Not all polyps develop into cancer, and it can take years for a polyp to evolve into cancer.
  • Colorectal cancer, as well as malignancies of the pancreas, liver, stomach, ovaries, thyroid, lungs, and breast, are associated with high levels.
  • Emphysema, A lung condition that affects the alveoli (tiny air sacs). The alveoli walls are where oxygen and carbon dioxide are exchanged in the lungs. The alveoli become abnormally expanded in emphysema, weakening their walls and making breathing difficult.

Carcinomas develop from epithelial tissue, which lines and covers organs and includes the skin. According to the National Cancer Institute, carcinomas account for 80 to 90% of cancer cases. Adenocarcinomas are cancers that originate in a gland or organ, most commonly the mucus membrane. CEA can be produced by any cancer that is characterized as an adenocarcinoma.

CEA can be employed for the following conditions:

Because elevated CEA levels can be caused by a variety of cancers and noncancerous ailments, professionals don’t utilise CEA tests to diagnose cancer or determine if the individual has it. Rather, they use to track how well specific treatments are responding.

CEA is one of many cancer indicators. Tumour markers are proteins or other chemicals found in or produced by cancer cells, which are then discharged into the bloodstream. They can tell you a lot about a patient’s cancer and how likely it is to respond to different treatments.

CEA is sometimes found in the spinal fluid or in the fluid in the abdomen wall. A fine needle and/or syringe will be used to collect a little sample of fluid for these tests. Fluids that can be evaluated include:

  • CSF is a clear, colourless liquid that is present in the spinal cord.
  • The fluid that borders your belly wall is called peritoneal fluid.
  • Pleural fluid is a liquid that covers the outside of each lung in your chest cavity.

Other cancer tests include:

  • CA-125 is a marker for ovarian, fallopian tube, or peritoneal cancer (a layer of tissue enclosing the abdominal organs).
  • HCG, or human chorionic gonadotropin, is a marker of cancer of the ovaries, testicles, or the cavities between the lungs or behind the intestines.
  • CA 19-9 is correlated to the bile duct or pancreatic cancer.

Reference ranges

The normal range for CEA is 3 nanograms per millilitre (ng/mL) or less. CEA concentrations that are more than 3 ng/mL are classified as elevated. This might be linked to a variety of conditions other than cancer, such as:

  • Irritable bowel syndrome (IBS) is a common gastrointestinal condition affecting the large intestine.
  • Infections such as pneumonia and SARS-CoV-2 can elevate CEA levels.
  • Cirrhosis is a late stage of liver scarring (fibrosis) caused by a variety of diseases and disorders, including hepatitis and chronic alcoholism.
  • Smoking Addiction

Even though even heavy smokers have higher CEA levels, it is less than 5 ng/ml. A CEA level of further than 20 ng/ml is exceedingly high and almost suggests malignancy.

Clinical significance

CEA is a tumour marker that can be found in cases of colorectal, gastrointestinal, lung, and breast cancers. CEA is a glycoprotein with a molecular mass of 150 to 300 kilodalton and carbohydrate content of 45-55 per cent.

CEA testing could be used based on the clinical staging. Colon cancer is strongly indicated by persistently increased values that are 5-10 times the upper reference range. CEA lowered after the effective first treatment. Elevated CEA levels might signal that the illness has persisted. Breast, lung, stomach, and pancreatic carcinomas can all be detected from CEA.


Yash Batra

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