Test Catalog

Test Id : K818

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Keratin 8 and 18 (KRT8/18), Technical Component only

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Overview

Test Catalog

Useful For
Suggests clinical disorders or settings where the test may be helpful

Aiding in the diagnosis of carcinomas

Reflex Tests
Lists tests that may or may not be performed, at an additional charge, depending on the result and interpretation of the initial tests.

Test Id Reporting Name Available Separately Always Performed
IHTOI IHC Initial, Tech Only No No
IHTOA IHC Additional, Tech Only No No

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

For the initial technical component only immunohistochemical (IHC) stain performed, the appropriate bill-only test ID will be reflexed and charged (IHTOI). For each additional technical component only IHC stain performed, an additional bill-only test ID will be reflexed and charged (IHTOA).

Method Name
A short description of the method used to perform the test

Immunohistochemistry (IHC)

NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.

Yes

Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test

Keratin 8/18 IHC, Tech Only

Aliases
Lists additional common names for a test, as an aid in searching

K8 and K18

KO

CK8 and CK18

CK-8 and CK-18

CYK8 and CYK18

K2C8

CARD2

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

For the initial technical component only immunohistochemical (IHC) stain performed, the appropriate bill-only test ID will be reflexed and charged (IHTOI). For each additional technical component only IHC stain performed, an additional bill-only test ID will be reflexed and charged (IHTOA).

Specimen Type
Describes the specimen type validated for testing

TECHONLY

Ordering Guidance

This test includes only technical performance of the stain (no pathologist interpretation is performed). If diagnostic consultation by a pathologist is required order PATHC / Pathology Consultation.

Shipping Instructions

Attach the green "Attention Pathology" address label (T498) and the pink Immunostain Technical Only label included in the kit to the outside of the transport container.

Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing

Specimen Type: Tissue

Supplies: Immunostain Technical Only Envelope (T693)

Container/Tube: Immunostain Technical Only Envelope

Preferred:

Formalin-fixed, paraffin-embedded tissue block

OR

2 Unstained, positively charged glass slides (25- x 75- x 1-mm) per test ordered; sections 4-microns thick

Acceptable: None

Digital Image Access

1. Information on accessing digital images of immunohistochemical (IHC) stains and the manual requisition form can be accessed through this website: https://news.mayocliniclabs.com/pathology/digital-imaging/

2. Clients ordering stains using a manual requisition form will not have access to digital images.

3. Clients wishing to access digital images must place the order for IHC stains electronically. Information regarding digital imaging can be accessed through this website: https://news.mayocliniclabs.com/pathology/digital-imaging/#section3

Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected

Wet/frozen tissue
Cytology smears
Nonformalin fixed tissue
Nonparaffin embedded tissue
Noncharged slides
ProbeOn slides
Snowcoat slides 		Reject

Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included

Specimen Type Temperature Time Special Container
TECHONLY Ambient (preferred)
Refrigerated

Useful For
Suggests clinical disorders or settings where the test may be helpful

Aiding in the diagnosis of carcinomas

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

For the initial technical component only immunohistochemical (IHC) stain performed, the appropriate bill-only test ID will be reflexed and charged (IHTOI). For each additional technical component only IHC stain performed, an additional bill-only test ID will be reflexed and charged (IHTOA).

Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Keratin 8 and 18 (KRT8/18) are expressed in a wide variety of epithelial cells. KRT8/18 is not expressed in mesenchymal cells or in endothelium. KRT8/18 is primarily used in the diagnosis of carcinomas including but not limited to mesotheliomas, renal cell carcinomas, small cell carcinomas, as well as most squamous cell carcinomas and adenocarcinomas.

Interpretation
Provides information to assist in interpretation of the test results

This test does not include pathologist interpretation, only technical performance of the stain. If interpretation is required, order PATHC / Pathology Consultation for a full diagnostic evaluation or second opinion of the case.

 

The positive and negative controls are verified as showing appropriate immunoreactivity. If a control tissue is not included on the slide, a scanned image of the relevant quality control tissue is available upon request; call 855-516-8404.

 

Interpretation of this test should be performed in the context of the patient's clinical history and other diagnostic tests by a qualified pathologist.

Cautions
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Age of a cut paraffin section can affect immunoreactivity. Stability thresholds vary widely among published literature and are antigen dependent. Best practice is for paraffin sections to be cut within 6 weeks.

Clinical Reference
Recommendations for in-depth reading of a clinical nature

1. Chavez JD, Schweppe DK, Eng JK, et al. Quantitative interactome analysis reveals a chemoresistant edgotype. Nat Commun. 2015;6:7928. doi:10.1038/ncommx8928

2. Vyberg M, Diernaes C, Roge R, et al. NordiQC assessments of low molecular weight keratin 8/18 immunoassays. Appl Immunohistochem Mol Morphol. 2017;25(10):673-678

3. Morice WG, Ferreiro JA. Distinction of basaloid squamous cell carcinoma from adenoid cystic and small cell undifferentiated carcinoma by immunohistochemistry. Hum Pathol. 1998;29(6):609-612

4. Iwata J, Fletcher CD. Immunohistochemical detection of cytokeratin and epithelial membrane antigen in leiomyosarcoma: a systematic study of 100 cases. Pathol Int. 2000;50(1):7-14

Method Description
Describes how the test is performed and provides a method-specific reference

Immunohistochemistry on sections of paraffin-embedded tissue.(Unpublished Mayo method)

PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information

No

Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.

Monday through Friday

Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

1 to 3 days

Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

Until staining is completed

Performing Laboratory Location
Indicates the location of the laboratory that performs the test

Rochester

Fees
Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.

  • Authorized users can sign in to Test Prices for detailed fee information.
  • Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
  • Prospective clients should contact their account representative. For assistance, contact Customer Service.

Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.

CPT codes are provided by the performing laboratory.

88342-TC, primary

88341-TC, if additional IHC

LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.

Test Id Test Order Name Order LOINC Value
K818 Keratin 8/18 IHC, Tech Only No LOINC Needed
Result Id Test Result Name Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
622525 Keratin 8/18 IHC, Tech Only No LOINC Needed

Test Setup Resources

Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

Excel | Pdf

Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports

Test Update Resources

Change Type Effective Date
New Test 2025-04-01