Immunohistochemistry Chromogranin-A (CGA) Test
Short Name: IHC CGA Test
Also known as: Chromogranin-A IHC Test, CGA Immunohistochemistry Test, IHC for Chromogranin-A, Neuroendocrine Marker CGA Test
Immunohistochemistry Chromogranin-A (CGA) Test test available at DNA Labs India for ₹3,000. Uses Immunohistochemistry (IHC) on Tumor tissue in 10% Formal-saline OR Formalin Fixed Paraffin Embedded (FFPE) block samples. Results in 5-7 working days from sample receipt. Block specimens typically take 5 days; large complex tissue specimens may take up to 7 days.. 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 purpose of the Immunohistochemistry Chromogranin-A (CGA) test is to detect the presence of Chromogranin-A protein in tissue samples, which serves as a definitive marker for neuroendocrine differentiation. This test is essential for confirming the diagnosis of neuroendocrine tumors, distinguishing them from other malignancies, classifying tumor type, and aiding in the selection of appropriate treatment strategies including surgery, chemotherapy, or targeted therapy.
- Test Code
- 989
- CPT Code
- 88342
- ICD Code
- C7A.0
- Price
- ₹3,000
- Sample Type
- Tumor tissue in 10% Formal-saline OR Formalin Fixed Paraffin Embedded (FFPE) block
- Result Time
- 5-7 working days from sample receipt. Block specimens typically take 5 days; large complex tissue specimens may take up to 7 days.
- Fasting Required
- No
- Method
- Immunohistochemistry (IHC)
Sample Collection
Provide a copy of the histopathology report, site of biopsy, and relevant clinical history. No fasting or special preparation is required for the patient. The referring clinician ensures adequate tissue is obtained during biopsy or surgery.
Method: Tissue Biopsy / Surgical Resection specimen
Laboratory Analysis
Tissue specimen is collected via biopsy or surgical resection by the treating surgeon or interventional radiologist under sterile conditions.
Report Delivery
The tissue sample is immediately placed in 10% formal-saline or processed into a formalin-fixed paraffin-embedded (FFPE) block and transported to the laboratory at room temperature along with a copy of the histopathology report and clinical history.
Timeline: 5-7 working days from sample receipt. Block specimens typically take 5 days; large complex tissue specimens may take up to 7 days.
Patient Instructions
About This Test
Who Should Get This Test
The purpose of the Immunohistochemistry Chromogranin-A (CGA) test is to detect the presence of Chromogranin-A protein in tissue samples, which serves as a definitive marker for neuroendocrine differentiation. This test is essential for confirming the diagnosis of neuroendocrine tumors, distinguishing them from other malignancies, classifying tumor type, and aiding in the selection of appropriate treatment strategies including surgery, chemotherapy, or targeted therapy.
How to Prepare
- Submit tumor tissue in 10% Formal-saline OR Formalin Fixed Paraffin Embedded (FFPE) block
- Ship the specimen at room temperature
- Provide a copy of the histopathology report
- Include the site of biopsy information
- Include detailed clinical history and indication for testing
Doctor's Notes
Reviewed by Dr Pasupathy Arumugam — MBBS, MD (Pathology) · Reg. No. 21521
"Immunohistochemistry for Chromogranin-A is a cornerstone marker in the diagnosis of neuroendocrine tumors. When combined with Synaptophysin and Ki-67, it helps accurately classify the tumor grade and guide treatment strategy. I recommend this test for any patient presenting with a suspected neuroendocrine neoplasm on imaging or biopsy."
Last medically reviewed: September 7, 2026
Test Parameters & Specifications
Sample Stability
- Tissue specimen not adequately fixed in formalin
- Specimen received without histopathology report or clinical history
- Severely necrotic or autolysed tissue with no viable tumor cells
- Specimen leaking or improperly labeled
- FFPE block with excessive decalcification artifact
Understanding Your Results
CGA Positive (Strong, >50% cells)
Confirms neuroendocrine origin of the tumor. Guides treatment decisions including surgical resection, somatostatin analogs, or targeted therapy.
CGA Positive (Weak/Moderate, <50% cells)
May require additional immunohistochemical workup including Synaptophysin, NSE, Ki-67, and CD56 for confirmation.
CGA Negative
If Synaptophysin is also negative, the tumor is unlikely to be of neuroendocrine origin. Clinical and imaging correlation is essential.
Consult your oncologist or treating physician if your CGA test result is positive, if you experience symptoms such as flushing, chronic diarrhea, abdominal pain, unexplained weight loss, or if your imaging studies suggest a neuroendocrine tumor. Early consultation enables timely diagnosis and treatment planning.
Limitations
- ⚠This test is performed on tissue biopsy; it is not a blood-based test
- ⚠A negative CGA result does not completely exclude a neuroendocrine tumor, as some NETs may not express CGA
- ⚠Results should be interpreted in conjunction with Synaptophysin, Ki-67, and clinical findings
- ⚠Tissue quality and fixation significantly impact test accuracy
- ⚠Not suitable for differentiating benign from malignant neuroendocrine lesions alone
Risks & Considerations
- ●This test is performed on an already-collected tissue specimen and poses no additional risk to the patient
- ●Risks are associated with the biopsy procedure itself, not the IHC test, and include bleeding, infection, or discomfort at the biopsy site
Interfering Factors
- ●Inadequate fixation of tissue specimen leading to antigen degradation
- ●Prolonged storage of FFPE blocks beyond recommended duration
- ●Use of over-fixation or under-fixation in formalin
- ●Necrotic or heavily calcified tumor tissue may yield false-negative results
- ●Decalcification agents may affect antigen preservation
Compare With Similar Tests
| Test | Immunohistochemistry Chromogranin-A (CGA) Test | Serum Chromogranin-A Blood Test | Immunohistochemistry Synaptophysin Test | Ki-67 Proliferation Index Test |
|---|---|---|---|---|
| Comparison | Immunohistochemistry Chromogranin-A (CGA) Test |
Frequently Asked Questions
What is the Immunohistochemistry Chromogranin-A (CGA) test?
Why is the IHC Chromogranin-A test performed?
What sample is required for the IHC CGA test?
Is fasting required for the Chromogranin-A IHC test?
What does a positive CGA immunohistochemistry result mean?
What does a negative CGA IHC result mean?
How long does it take to get the IHC CGA test results?
What is the cost of the IHC Chromogranin-A test in India?
Is home sample collection available for this test?
What are neuroendocrine tumors (NETs)?
Is the IHC CGA test the same as the serum Chromogranin-A blood test?
Can the IHC Chromogranin-A test detect all types of neuroendocrine tumors?
Related Tests
Reference Laboratory Services
We serve as a reference laboratory for hospitals and clinics across India. Send samples from your facility with same-day pickup, priority processing, and results delivered through our online portal. Competitive institutional pricing available.
Your Data Privacy
Your medical data is protected under Indian law.
✓ Stored in India: All patient records are stored on servers located in India. No data is transferred outside the country.
✓ DPDP Act Compliant: Under the Digital Personal Data Protection Act 2023, you can request deletion of your records at any time by contacting support.
Book Your Test
Enter your details and we'll connect you within 15 minutes.