Assay Description

Cytokeratins are polypeptide chains that form structural proteins within the epithelial cell cytoskeleton. Nineteen different molecular forms of cytokeratin have been identified in both normal and malignant epithelial cell lines.1 Because specific combinations of cytokeratin peptides are associated with different epithelial cells, these peptides are clinically important markers for classifying carcinomas (tumors of epithelial origin)2 and for distinguishing carcinomas from malignant tumors of nonepithelial origin such as lymphomas, melanomas, and sarcomas. The identification of cytokeratin has gained increasing importance in immunopathology. A scheme for the use of anti-cytokeratin in the classification of tumors is presented in the current Manual of Clinical Laboratory Immunology, Chapter 145.5.3.

Specimen Requirements

A formalin-fixed, paraffin-embedded (FFPE) tissue block is preferred specimen type or one (1) unbaked, unstained slide cut at 4-5 microns for H&E staining (required) and two to three (2-3) positively charged unstained slides cut at 3-4 microns for each test/antibody ordered.

Storage and Transport

Use cold pack during transport of paraffin blocks and unstained slides. Cold pack should not be placed in direct contact with the specimen during shipping.

Specimen Rejection Criteria

All specimens must be submitted according to the test directory instructions.  Before submitting specimen, please carefully review specimen requirements.

Listed below are possible causes for delays in specimen processing or possible specimen rejections or cancellations:

• No patient identification on requisition form
• No patient identification on specimen container or slides
• No referring provider
• No account information provided
• No test ordered on requisition
• No specimen source provided
• Inappropriate specimen type
• Insufficient volume for analysis
• Inappropriate specimen container
• Improper specimen transport
• Specimen leaked in transport
• Specimen submitted in incorrect or expired transport media
• Slides broken beyond repair on receipt
• Conflict between patient name on specimen and requisition form
• Specimen not properly preserved
• Sample containing a needle

A representative from Client Services will attempt to contact your office  to resolve specimen problems.  Additional documentation may be requested from your office to be returned by fax.  In the event that resolution is not possible, the specimen may be returned to your office.

Storage and Transport

Use cold pack during transport of paraffin blocks and unstained slides. Cold pack should not be placed in direct contact with the specimen during shipping.

Specimen Rejection Criteria

All specimens must be submitted according to the test directory instructions.  Before submitting specimen, please carefully review specimen requirements.

Listed below are possible causes for delays in specimen processing or possible specimen rejections or cancellations:

• No patient identification on requisition form
• No patient identification on specimen container or slides
• No referring provider
• No account information provided
• No test ordered on requisition
• No specimen source provided
• Inappropriate specimen type
• Insufficient volume for analysis
• Inappropriate specimen container
• Improper specimen transport
• Specimen leaked in transport
• Specimen submitted in incorrect or expired transport media
• Slides broken beyond repair on receipt
• Conflict between patient name on specimen and requisition form
• Specimen not properly preserved
• Sample containing a needle

A representative from Client Services will attempt to contact your office  to resolve specimen problems.  Additional documentation may be requested from your office to be returned by fax.  In the event that resolution is not possible, the specimen may be returned to your office.

Turn Around Time (TAT)

2-3 Days.

CPT Codes*

88341, 88342, 88360