Immunohistochemistry Cytokeratin-19 (CK-19) Test
Short Name: CK-19 IHC Test
Also known as: CK-19 IHC Test, Cytokeratin-19 Immunohistochemistry, CK19 Staining, Anti-Cytokeratin-19 Antibody Test
Immunohistochemistry Cytokeratin-19 (CK-19) Test test available at DNA Labs India for ₹3,500. Uses Immunohistochemistry (IHC) on Tumor Tissue samples. Results in Block specimens: 5 working days. Tissue biopsy: 5 working days. Large or complex tissue specimens: 7 working days. Reports are available by 6 PM on the day of report generation.. Free home collection in 300+ cities across India.
🩺 Medically Reviewed By
Dr Pasupathy Arumugam
Consultant Pathologist · Reg: 21521
Last reviewed: September 7, 2026
Overview
The primary purpose of the CK-19 immunohistochemistry test is to detect Cytokeratin-19 protein expression in tissue specimens to aid in the diagnosis, classification, and differential diagnosis of epithelial-derived malignancies. It helps identify tumours with ductal or glandular differentiation, confirm epithelial origin of metastatic deposits, and support the pathologist in determining the likely primary site when metastatic carcinoma of unknown origin is suspected.
- Test Code
- 993
- CPT Code
- 88342
- ICD Code
- C34.9
- Price
- ₹3,500
- Sample Type
- Tumor Tissue
- Result Time
- Block specimens: 5 working days. Tissue biopsy: 5 working days. Large or complex tissue specimens: 7 working days. Reports are available by 6 PM on the day of report generation.
- Fasting Required
- No
- Method
- Immunohistochemistry (IHC)
Sample Collection
Ensure a biopsy or surgical tissue specimen has been collected by the treating physician or surgeon. Provide a copy of the histopathology report, the site of biopsy, and the patient's clinical history along with the specimen.
Method: Tissue Biopsy / Surgical Resection
Laboratory Analysis
The tissue specimen is collected via core needle biopsy, excisional biopsy, or surgical resection by a qualified clinician. The specimen is immediately placed in 10% formal-saline or processed into a formalin-fixed paraffin-embedded (FFPE) block to preserve tissue architecture and antigen integrity.
Report Delivery
Label the specimen container correctly with patient details. Ship the specimen at room temperature. Include all relevant clinical documentation to ensure accurate interpretation by the reporting pathologist.
Timeline: Block specimens: 5 working days. Tissue biopsy: 5 working days. Large or complex tissue specimens: 7 working days. Reports are available by 6 PM on the day of report generation.
Patient Instructions
About This Test
Who Should Get This Test
The primary purpose of the CK-19 immunohistochemistry test is to detect Cytokeratin-19 protein expression in tissue specimens to aid in the diagnosis, classification, and differential diagnosis of epithelial-derived malignancies. It helps identify tumours with ductal or glandular differentiation, confirm epithelial origin of metastatic deposits, and support the pathologist in determining the likely primary site when metastatic carcinoma of unknown origin is suspected.
How to Prepare
- Submit tumor tissue in 10% formal-saline or as a formalin-fixed paraffin-embedded (FFPE) block
- Ship the specimen at room temperature; do not freeze
- Provide a copy of the histopathology report with the specimen
- Include the site of biopsy and relevant clinical history
- Ensure proper labelling of the specimen container with patient name, date, and specimen source
Doctor's Notes
Reviewed by Dr Pasupathy Arumugam — MBBS, MD (Pathology) · Reg. No. 21521
"Cytokeratin-19 immunohistochemistry is a valuable ancillary marker in the workup of carcinomas, particularly for identifying ductal/glandular differentiation in breast, lung, thyroid and pancreatic tumours. It should always be interpreted in conjunction with morphology and a panel of other immunohistochemical markers rather than in isolation. Speak with your oncologist about whether CK-19 staining is relevant to your diagnostic or treatment planning pathway."
Last medically reviewed: September 7, 2026
Test Parameters & Specifications
Sample Stability
- Specimen received without proper labelling or identification
- Tissue fixed in incorrect fixative or inadequately fixed specimen
- Severely autolysed or necrotic tissue with no viable tumour cells
- Missing clinical history or histopathology report
- Specimen received in expired or leaking containers
Understanding Your Results
Confirms expression of Cytokeratin-19 in the neoplastic cells. Consistent with epithelial-derived carcinoma showing ductal or glandular differentiation. Commonly seen in breast ductal carcinoma, pulmonary adenocarcinoma, thyroid papillary/follicular carcinoma, pancreatic ductal adenocarcinoma, and ovarian carcinomas. Interpret in the context of morphology and a broader IHC panel.
No detectable CK-19 expression in the submitted tissue. This does not exclude malignancy. Some carcinomas (e.g., certain squamous cell carcinomas or high-grade neuroendocrine tumours) may lack CK-19 expression. Consider additional markers and clinical correlation. Repeat testing on a different tissue block may be warranted if clinical suspicion remains high.
Consult your oncologist or treating physician if the CK-19 test result is unexpected, if there is discordance between the IHC result and clinical/imaging findings, or if further characterisation of the tumour is needed for treatment planning. Any newly diagnosed cancer or suspicion of metastatic disease warrants prompt specialist consultation.
Limitations
- ⚠CK-19 staining is not specific to a single cancer type; it is expressed in multiple epithelial-derived tumours and must be interpreted alongside other markers
- ⚠A negative CK-19 result does not exclude malignancy; some carcinomas may show reduced or absent CK-19 expression
- ⚠This test is intended for use on tissue specimens only and is not validated for liquid biopsy or circulating tumour cell detection
- ⚠Results are qualitative and should always be reviewed by a qualified pathologist in conjunction with histomorphology, clinical history, and a panel of ancillary immunohistochemical stains
- ⚠Sample quality is critical — inadequate or degraded tissue may yield non-diagnostic results
Risks & Considerations
- ●As this is a laboratory test performed on an already-collected tissue specimen, there are no direct physical risks to the patient from the IHC procedure itself
- ●The biopsy or surgical procedure used to collect the tissue specimen carries inherent procedural risks such as bleeding, infection, or discomfort at the biopsy site, which are managed by the collecting clinician
- ●There is a small possibility of a non-diagnostic result if the tissue quality is suboptimal, which may require re-biopsy
Interfering Factors
- ●Prolonged or improper fixation of tissue (over-fixation or under-fixation) may affect antigen preservation and staining intensity
- ●Decalcification of bony tissue specimens can degrade antigens and yield false-negative results
- ●Excessive tissue necrosis or autolysis may compromise staining quality
- ●Use of expired or improperly stored antibody reagents may lead to unreliable results
Compare With Similar Tests
| Test | Immunohistochemistry Cytokeratin-19 (CK-19) Test | Immunohistochemistry CK-7 | Immunohistochemistry CK-20 | Immunohistochemistry TTF-1 | Immunohistochemistry EMA (Epithelial Membrane Antigen) |
|---|---|---|---|---|---|
| Comparison | Immunohistochemistry Cytokeratin-19 (CK-19) Test | CK-7 is another low-molecular-weight cytokeratin marker often used alongside CK-19. While CK-19 highlights ductal/glandular differentiation, CK-7 is helpful in distinguishing pulmonary adenocarcinoma (CK-7 positive) from squamous cell carcinoma and in identifying tumours of breast, lung, and ovarian origin. | CK-20 is typically expressed in colorectal carcinomas, Merkel cell carcinomas, and some urothelial tumours. A CK-19 positive/CK-20 negative profile is characteristic of upper gastrointestinal, pancreaticobiliary, and breast carcinomas, while a CK-20 positive/CK-19 variable profile supports a colorectal primary. | TTF-1 (Thyroid Transcription Factor-1) is a nuclear marker used to confirm pulmonary or thyroid origin of a carcinoma. It is frequently ordered alongside CK-19 in the workup of lung adenocarcinoma and thyroid carcinoma to provide complementary diagnostic information. | EMA is a broad epithelial marker that, like CK-19, confirms epithelial differentiation. It is used in combination with CK-19 and other cytokeratins to build a comprehensive IHC panel for tumour classification and origin determination. |
Frequently Asked Questions
What is the CK-19 immunohistochemistry test?
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Can CK-19 be detected through a blood test instead of tissue biopsy?
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