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Carcinoembryonic Antigen (CEA) by Immunoassay (Serum)

Published: August 9, 2026Updated: August 17, 2026

This test measures the levels of carcinoembryonic antigen (CEA), a protein sometimes produced by certain cancers, including colorectal, lung, and breast cancers. It helps doctors monitor these conditions and track how a cancer is responding to treatment.

Quick summary

["CEA levels can help detect or track cancer progression and treatment effectiveness."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
68927-3
Short code
CK 19 Prt-mCnc
Synonyms
CK 19 Prt-mCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
22
Ref high
198
Critical range
— – 10000 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
82553
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

What Is Carcinoembryonic Antigen (CEA)?

CEA is a protein found in small amounts in the blood of most people. It is produced by fetal tissues during development but is usually absent in healthy adults. In some cancers, such as colorectal or lung cancer, CEA levels can rise, making it a useful marker for diagnosis, monitoring, or recurrence.

Why Might You Need This Test?

Your doctor may order a CEA test if you have a history of cancer, symptoms like unexplained weight loss, fatigue, or changes in bowel habits, or if you’re undergoing cancer treatment to check for recurrence. It can also be used as a screening tool in certain high-risk groups.

How Is the Test Performed?

A blood sample is drawn from a vein in your arm. The sample is sent to a lab, where it is tested using an immunoassay method to detect and measure CEA protein levels.

What Do the Results Mean?

Results are reported in nanograms per milliliter (ng/mL). Higher than normal levels may indicate cancer, but they can also be influenced by other factors like smoking, liver disease, or inflammation. Your doctor will interpret results in the context of your medical history and symptoms.

Reference range

Adult males: 22-198 U/L; Females: 22-198 U/LN/A

Specimen: serum

No special preparation required. Inform provider of any chest pain or symptoms.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CEA Serum

Frequently asked questions

What causes CEA levels to change?
CEA levels can be influenced by cancer, but other factors like smoking, liver disease, infections, or certain medications may also affect them. If you have non-cancer conditions or take medications that affect liver function, your doctor may adjust interpretation accordingly.
Can CEA levels be affected by diet or lifestyle?
While diet and lifestyle factors like smoking may indirectly influence CEA levels (e.g., smoking is linked to higher CEA in some cancers), the protein itself is not directly affected by diet. Your doctor will consider lifestyle factors when evaluating results alongside clinical context.
How often should CEA levels be checked?
Frequency depends on your medical history and treatment plan. For cancer patients, CEA may be checked regularly during and after treatment to monitor for recurrence. Your doctor will determine the best schedule based on your specific situation.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 17, 2026. · Read our editorial policy