Cytokeratin 19 mRNA for Metastasis, Lymph Node — Qualitative Nucleic Acid Probe
A lymph node tissue test that detects CK19 mRNA to help identify epithelial tumor cells, commonly used when evaluating breast cancer spread.
["This test checks lymph node tissue for CK19 mRNA, a marker that can be found in some cancer cells."]
Key facts at a glance
- LOINC
- 104127-6
- Short code
- CK19 mRNA metastasis LN Ql NAA+n-prb
- Synonyms
- CK19 mRNA metastasis LN Ql NAA+n-prb
- Category
- liver
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 10
- Ref high
- 40
- Critical range
- — – 10000 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- non-probe-amp-tar
- CPT
- 84484
- SNOMED
- 302774002
- 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 this test?
This qualitative test examines lymph node tissue for cytokeratin 19 (CK19) messenger RNA. CK19 is produced by many epithelial cells, including some breast cancer cells, so the test can help identify tumor involvement in a sampled lymph node.
Why might I need this test?
This test is commonly used during breast cancer evaluation to help determine whether cancer cells have spread to a lymph node. It is usually performed on a surgically removed or biopsied lymph node and is interpreted along with pathology and other clinical findings.
How is the test performed?
A laboratory uses a nucleic acid probe to detect CK19 mRNA in lymph node tissue. The result is reported qualitatively, generally as detected or not detected, rather than as a numeric measurement.
How do I prepare for the test?
No special preparation is usually required because the test uses lymph node tissue obtained during a biopsy or surgery. Follow your clinician's instructions for the lymph node sampling procedure and discuss any questions about the result.
Reference range
Adult: 10-40 U/LN/A
No special preparation required. Avoid fatty meals before the test if possible.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Detection of CK19 mRNA may indicate the presence of CK19-expressing epithelial tumor cells in the lymph node and can support concern for metastatic involvement. However, a positive result should be interpreted with pathology and clinical findings because benign epithelial cells or laboratory factors may also influence the result. A result that is not detected does not completely exclude cancer, particularly in tumors that do not express CK19.
Short name
CK19 mRNA Lymph Node Test
Frequently asked questions
Does this test use blood?
What does a positive result mean?
Does a negative result mean there is no cancer?
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