This is a test that measures the amount of carcinoembryonic antigen (CEA) in blood.
How the test is performed
Blood is drawn from a vein (venipuncture), usually from the inside of the elbow or the back of the hand. The puncture site is cleaned with antiseptic, and a tourniquet (an elastic band) or blood pressure cuff is placed around the upper arm to apply pressure and restrict blood flow through the vein. This causes veins below the tourniquet to distend (fill with blood).
A needle is inserted into the vein, and the blood is collected in an airtight vial or a syringe. During the procedure, the tourniquet is removed to restore circulation. Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.
Infant or young child:
The area is cleansed with antiseptic and punctured with a sharp needle or a lancet. The blood may be collected in a pipette (small glass tube), on a slide, onto a test strip, or into a small container. Cotton or a bandage may be applied to the puncture site if there is any continued bleeding.
How to prepare for the test
Smokers may be asked to refrain from smoking for a short time before the test because smoking may increase CEA levels.
Infants and children:
The physical and psychological preparation you can provide for this or any test or procedure depends on your child’s age, interests, previous experiences, and level of trust. For specific information regarding how you can prepare your child, see the following topics as they correspond to your child’s age:
- Infant test or procedure preparation (birth to 1 year)
- Toddler test or procedure preparation (1 to 3 years)
- Preschooler test or procedure preparation (3 to 6 years)
- Schoolage test or procedure preparation (6 to 12 years)
- Adolescent test or procedure preparation (12 to 18 years)
How the test will feel
When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.
Why the test is performed
CEA is a protein that normally occurs in fetal gut tissue. After birth, detectable serum levels essentially disappear. However, CEA may increase in the presence of various disorders such as colon cancer.
This test may also be used to determine the responsiveness of cancer patients to treatment (to determine if cancer is spreading or going into remission).
The normal range is 0 to 2.5 mcg/L ( less than 3 ng/mL).
mcg/L = micrograms per liter
ng/mL = nanograms per milliliter
What abnormal results mean
Greater-than-normal levels may indicate:
- Colon cancer
- Breast cancer
- Lung cancer
- Pancreatic cancer
- Thyroid cancer
- Genitourinary carcinomas
- Inflammatory gastrointestinal diseases (for example, ulcerative colitis, diverticulitis, cholecystitis, pancreatitis)
- Other liver disease
- Peptic ulcer
- Heavy smoking
- Pulmonary infections
What the risks are
- Excessive bleeding
- Fainting or feeling lightheaded
- Hematoma (blood accumulating under the skin)
- Infection (a slight risk any time the skin is broken)
- Multiple punctures to locate veins
This test is most useful to follow response to treatment in patients with known cancer. Abnormal levels can be found in patients without cancer. Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample may be more difficult from some people than from others.
by Martin A. Harms, M.D.
All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.