Cancer Antigen 15-3 (CA 15-3) Tumor Marker, Aspirate Fluid
This test measures a protein produced by certain types of cancer cells, often found in breast, ovarian, or other malignancies, within fluid collected from a tumor aspiration procedure.
["Helps assess cancer presence or recurrence in fluid samples from suspicious masses."]
Key facts at a glance
- LOINC
- 97749-6
- Short code
- CA153
- Synonyms
- Cancer Ag15-3 Aspirate-aCnc
- Category
- chemistry
- Sample
- serum
- Container
- Red-top serum collection tube or serum separator tube (SST)
- Units
- N/A
- Ref low
- 0
- Ref high
- 30
- Critical range
- 0.5 N/A – 100 N/A
- Fasting
- false
- Population
- adult
- Sex
- female
- Age range
- 18–99 years
- Method
- chemiluminescent immunoassay (CLIA)
- CPT
- 86300
- SNOMED
- 11526-1
- Specimen volume
- 1-2 mL of aspirate fluid in serum tube
- Stability
- Room temperature: 8 hours; Refrigerated (2-8°C): 7 days; Frozen (-20°C): 3 months; Avoid repeated freeze-thaw cycles
- Hemolysis max
- 100
- Lipemia max
- 200
- Icterus max
- 40
- TAT
- 4–24 hours
- Order
- routine
Why This Test Is Done
Your doctor may order this test if you have a suspected tumor or cancer that has spread to fluid-filled spaces (such as lymph nodes or body cavities). Aspirate fluid is collected during a procedure to diagnose or monitor cancer progression.
What to Expect Before the Test
No special preparation is typically needed, but follow your doctor’s instructions regarding fasting or medications. The procedure may involve local anesthesia, and you’ll be monitored during fluid collection.
What the Test Results Mean
Higher levels of CA 15-3 in aspirate fluid may indicate cancer cells are present, but results alone don’t confirm diagnosis. Results are often compared to baseline or other tests for interpretation.
Common Causes of Elevated Results
Elevated CA 15-3 can occur in cancers like breast or ovarian cancer, but also in non-cancerous conditions such as benign tumors, inflammation, or prior chemotherapy.
Reference range
Normal: <30 U/mL; Values vary by laboratory; Consult reference range provided with patient reportN/A
No fasting required; Specimen collection by fine needle aspiration of breast cyst/mass; Inform clinician of any current medications including biotin supplements as they may interfere with assay
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
CA 15-3 in aspirate fluid is used to detect cancer cells in fluid samples, aiding in diagnosis or evaluating treatment response. It’s particularly useful when other tests (like imaging or biopsies) are inconclusive. However, it’s not a standalone test—results must be reviewed with clinical context.
Short name
CA 15-3 in Aspirate Fluid
Frequently asked questions
What does a positive result mean?
Can this test be used to detect early-stage cancer?
How often should I get this test?
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