Cytokeratin 7 (CK7) and Thyroid Transcription Factor-1 (TTF-1) Antigens, Tissue — Immunohistochemistry
A tissue pathology test that detects CK7 and TTF-1 proteins to help identify the likely origin of certain cancers.
["This test helps a pathologist classify certain cancers by showing whether tumor cells contain CK7 and TTF-1 proteins."]
Key facts at a glance
- LOINC
- 74491-2
- Short code
- CK7+TTF-1 Ag Tiss ImStn
- Synonyms
- CK7+TTF-1 Ag Tiss ImStn
- Category
- thyroid
- 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
- Method
- immune-stain
- 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 this test?
This is an immunohistochemical test performed on a tissue sample, usually a biopsy or surgical specimen. It uses antibodies to detect two proteins: cytokeratin 7 (CK7) and thyroid transcription factor-1 (TTF-1).
Why might I need this test?
Pathologists may use these stains when the tissue origin of a tumor is unclear. The pattern of staining can help narrow the possibilities, such as distinguishing among tumors that can resemble one another under the microscope.
How is the test performed?
A laboratory applies special antibodies to a prepared tissue slide and examines whether the tumor cells show staining. A pathologist interprets the results together with the tissue appearance, other laboratory tests, and your medical history.
How do I prepare for the test?
No special preparation is needed if tissue has already been collected. If a biopsy or surgery is required, follow the instructions provided by your healthcare team, including any medication or fasting directions.
Reference range
Adult males: 22-198 U/L; Females: 22-198 U/LN/A
No special preparation required. Inform provider of any chest pain or symptoms.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
CK7 and TTF-1 staining patterns can support or narrow a diagnosis of cancer, particularly when evaluating tumors that may arise from the lung, thyroid, breast, or another site. Neither stain is completely specific, so results should not be interpreted in isolation. Your doctor will explain how the findings fit with your pathology report and overall clinical picture.
Short name
CK7 and TTF-1 immunostains
Frequently asked questions
Does a positive CK7 or TTF-1 result mean I have cancer?
Is this test the same as a blood test?
How long does it take to get the results?
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.
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Medically reviewed by WellAlly Editorial Team Last reviewed August 17, 2026. · Read our editorial policy