Cancer Antigen 724 (CA 72.4) – Fluid Concentration
This test measures the concentration of a specific protein, CA 72.4, which may be produced by certain types of cancer, particularly those of the gastrointestinal tract.
["CA 72.4 helps detect or monitor certain cancers, though it’s not the only marker used."]
Key facts at a glance
- LOINC
- 34161-0
- Short code
- CA72-4
- Synonyms
- Cancer Ag72-4 Fld-aCnc
- Category
- chemistry
- Sample
- serum
- Container
- Red-top serum tube or serum separator tube (SST)
- Units
- N/A
- Ref low
- 0
- Ref high
- 6
- Critical range
- 0.5 N/A – —
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–99 years
- Method
- Immunoassay (chemiluminescent or electrochemiluminescent)
- CPT
- 86316
- SNOMED
- 1152683000
- Specimen volume
- 1-2 mL serum
- Stability
- Stable for 24 hours at room temperature, 7 days at 2-8°C, or 3 months at -20°C. Avoid repeated freeze-thaw cycles.
- Hemolysis max
- 100
- Lipemia max
- 200
- Icterus max
- 50
- TAT
- 24–72 hours
- Order
- routine
What Is CA 72.4?
CA 72.4 is a tumor-associated antigen found in higher levels in some cancers, such as gastric (stomach) and pancreatic cancers. It’s often used alongside other tests to aid in diagnosis, staging, or treatment monitoring. However, it can also appear in non-cancerous conditions, so results should always be interpreted by a healthcare provider in the context of your medical history and symptoms.
Why Might This Test Be Ordered?
Your doctor may order a CA 72.4 test if you have symptoms suggestive of gastrointestinal cancer (e.g., unexplained weight loss, abdominal pain, or changes in bowel habits), if you’ve been diagnosed with a cancer that may produce this marker, or as part of routine monitoring during treatment. It can also be used to check for recurrence after treatment.
How Is the Test Performed?
A blood sample is drawn from a vein in your arm. The blood is then sent to a lab for analysis. The test measures the amount of CA 72.4 protein in your serum or plasma. Results are typically reported as a concentration value, though reference ranges can vary by lab.
What Do the Results Mean?
Elevated levels of CA 72.4 may indicate the presence of cancer, but they can also be found in other conditions, such as chronic liver disease or certain infections. A low or normal result doesn’t definitively rule out cancer. Your doctor will discuss the results with you and may recommend additional testing if needed.
Reference range
Less than 6.0 U/mL (varies by assay manufacturer); values above the upper limit may indicate malignancy and warrant further clinical evaluationN/A
No fasting required. No special preparation needed. Inform clinician of any recent biological therapies or monoclonal antibody treatments as these may affect results.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance
Short name
CA 72.4 (Serum/Plasma)
Frequently asked questions
What are the typical reference ranges for CA 72.4?
Can CA 72.4 levels change over time?
Is this test always accurate?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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