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Carcinoembryonic Antigen (CEA) in Stool, Quantitative

Published: August 9, 2026Updated: August 16, 2026

This test measures the amount of carcinoembryonic antigen (CEA), a protein sometimes produced by certain cancers, in your stool. It may help detect or monitor colorectal cancer or other conditions affecting the digestive tract.

Quick summary

["CEA in stool can help track cancer growth or response to treatment."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
85499-2
Short code
KPC
Synonyms
blaKPC AnorectlIslt Ql NAA+probe
Category
chemistry
Sample
serum
Container
Sterile, leak-proof container for serum; preferred evacuated blood collection tubes without anticoagulants (red-top or serum separator tubes). Molecular testing may also be performed on blood culture broth, pure bacterial isolates, or rectal/perirectal swab eluates in transport medium depending on laboratory protocol.
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
≥ 0 years
Method
probe-amp-tar
CPT
87798 (Amplified probe technique, organism detection, not otherwise specified)
SNOMED
122450008 | 433601000124107
Specimen volume
5-10 mL whole blood for serum preparation (minimum 1 mL serum). For other specimen types, follow laboratory-specific requirements (typically 200 microliters to 1 mL of prepared specimen).
Stability
Serum: Room temperature 2-8 hours; refrigerated (2-8°C) up to 5 days; frozen (-70°C or lower) up to 30 days. Avoid repeated freeze-thaw cycles. Bacterial isolates should be tested from fresh cultures (24-48 hours old) when possible.
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

What Is Carcinoembryonic Antigen (CEA)?

CEA is a protein that can be found in small amounts in healthy people’s bodies, mostly in the digestive system. However, higher levels may indicate certain cancers, such as colorectal cancer, or other inflammatory or infectious conditions of the gastrointestinal tract.

Why Might You Need This Test?

Your doctor may order this test if you have symptoms like unexplained weight loss, changes in bowel habits, or if you’ve been diagnosed with colorectal cancer to monitor treatment progress or check for recurrence. It may also be used as part of a screening or diagnostic workup for digestive issues.

How Is the Test Done?

You’ll provide a sample of your stool, typically collected in a special container provided by your healthcare provider. The sample is then sent to a lab for analysis.

What Are the Possible Results?

Results are reported as a concentration of CEA in the stool. While reference ranges vary by lab, higher-than-normal levels may raise concerns about cancer or other digestive issues, prompting further testing.

Reference range

Negative (blaKPC gene not detected). A positive result indicates the presence of carbapenem-resistant Enterobacteriaceae (CRE) carrying the blaKPC gene, which is the most common carbapenemase gene in the United States and globally.N/A

Specimen: serum

No fasting required. Standard aseptic specimen collection techniques should be followed to prevent contamination. For serum samples, collect prior to initiation of antibiotic therapy when possible. Inform the laboratory of current or recent antimicrobial therapy.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance:

Short name

Stool CEA Test

Frequently asked questions

How often will I need this test?
This test is often used as part of a broader evaluation, such as follow-up after cancer treatment or screening for colorectal cancer. Your doctor will determine the frequency based on your medical history and needs.
What does a high or low CEA level mean?
Elevated levels may suggest colorectal cancer or other gastrointestinal conditions, but they can also be influenced by inflammation, infections, or other factors. Your doctor will interpret results in the context of your health history and other tests.
Can I eat or drink anything before the test?
Follow your doctor’s instructions regarding diet or preparation. Typically, you may need to avoid certain foods or medications for a few days before testing to ensure accurate results.
  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 16, 2026. · Read our editorial policy