Overview: Cytokeratin 20 Immunohistochemistry TestIntroduction: The Cytokeratin 20 Immunohistochemistry Test detects cytokeratin 20 (CK20) to diagnose colorectal cancer, causing abdominal pain or bleeding. Following 2023 NCCN guidelines, it uses immunohistochemistry for high specificity, supporting cancer screening. This test is critical for guiding diagnosis, treatment planning, and improving outcomes in histopathology for patients with suspected colorectal cancer.
Other Names: CK20 IHC Assay, Colorectal Cancer IHC Test.
FDA Status: Laboratory-developed test (LDT), meeting histopathology standards for diagnostic accuracy.
Historical Milestone: CK20 testing emerged in the 1990s with colorectal cancer research. Immunohistochemistry-based methods improved in the 2000s, enhancing diagnostic precision.
Purpose: Detects CK20 to diagnose colorectal cancer, guides treatment, and evaluates patients with abdominal pain or bleeding.
Test Parameters: 1. Cytokeratin 20 Protein
Pretest Condition: No fasting required. Collect tissue via biopsy or surgical resection. Report history of abdominal pain, bleeding, or bowel changes.
Specimen: 0.5-2 cma³ tissue (FFPE). Transport in a biohazard container.
Sample Stability at Room Temperature: 7 days
Sample Stability at Refrigeration: Not refrigerated
Sample Stability at Frozen: Not frozen
Medical History: Document abdominal pain, rectal bleeding, weight loss, or family history of colorectal cancer. Include current medications, especially chemotherapy.
Consent: Written consent required, detailing the tests purpose, cancer implications, and risks of biopsy or surgery.
Procedural Considerations: Uses immunohistochemistry to detect CK20 in colorectal tissue. Results are available in 1-2 days, supporting rapid clinical decisions. Performed in laboratories, often for colorectal cancer diagnosis.
Factors Affecting Result Accuracy: Improper tissue fixation or processing can affect results. Low tissue quality may reduce staining accuracy.
Clinical Significance: Positive CK20 staining suggests colorectal cancer, guiding surgery or chemotherapy. Negative staining may require further marker testing (e.g., CK7).
Specialist Consultation: Consult an oncologist or gastroenterologist for result interpretation and treatment planning.
Additional Supporting Tests: CK7 IHC, CEA, or colonoscopy to confirm colorectal cancer diagnosis.
Test Limitations: Not specific to colorectal cancer; other tumors (e.g., Merkel cell carcinoma) may express CK20. Clinical correlation is needed.
References: NCCN Colorectal Cancer Guidelines, 2023; American Journal of Surgical Pathology, Chu PG, 2022.
