Test Catalog

Test Id : KRASW

KRAS Somatic Mutation Analysis, Peritoneal Fluid

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

Detecting molecular markers associated with response or resistance to specific cancer

Special Instructions
Library of PDFs including pertinent information and forms related to the test

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

Droplet Digital Polymerase Chain Reaction (ddPCR)

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


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

KRAS Mutation Analysis, Peritoneal

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

Cetuximab (Erbitux)

Colorectal cancer



Epidermal growth factor receptor

Erbitux (Cetuximab)


KRAS codon 12

KRAS codon 13

KRAS codon 146

KRAS codon 61



Non-small cell lung cancer


Patiumumab (Vectibix)


Vectibix (Patiumumab)

Specimen Type
Describes the specimen type validated for testing


Necessary Information

Pathology report (final or preliminary) is required and must accompany specimen for testing to be performed. At minimum, it should contain the following information:

1. Patient name and second identifier

2. Fluid collection date

3. Source of the fluid

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

Container/Tube: 50-mL Falcon tube with fixative

Preferred: PreservCyt solution

Acceptable: CytoLyt solution, methanol:glacial acidic acid (3:1) fixative, or 50% or 80% ethanol

Specimen Volume: Two to four 50-mL Falcon tubes each containing fixed cells in equal volume to approved fixatives

Collection Instructions: Containers must be labeled with two unique patient identifiers.

Special Instructions
Library of PDFs including pertinent information and forms related to the test


Molecular Genetics: Inherited Cancer Syndromes Patient Information (T519)

Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the Testing Laboratory

100 mL of washing in acceptable fixative

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

No fixative added 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
Varies Ambient (preferred)

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

Detecting molecular markers associated with response or resistance to specific cancer

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

Strategies that focus on early detection and prevention effectively decrease the risk of mortality associated with cancer. In addition, an increase in survival rate for individuals with advanced stage disease has been observed as a result of advancements in standard chemotherapeutic agents and the development of specialized targeted therapies. Monoclonal antibodies against epidermal growth factor receptor (EGFR), such as cetuximab and panitumumab, represent an area of targeted therapy for patients with colorectal and non-small cell lung cancer (NSCLC). However, studies have shown that not all individuals with colorectal cancer or NSCLC respond to EGFR targeted molecules. Because the combination of targeted therapy and standard chemotherapy leads to an increase in toxicity and cost, strategies that help to identify the individuals most likely to benefit from such targeted therapies are desirable.


EGFR is a growth factor receptor that is activated by the binding of specific ligands (epiregulin and amphiregulin), resulting in activation of the RAS/MAPK (mitogen activated protein kinase) pathway. Activation of this pathway induces a signaling cascade ultimately regulating a number of cellular processes including cell proliferation. Dysregulation of the RAS/MAPK pathway is a key factor in tumor progression. Targeted therapies directed to EGFR, which inhibit activation of the RAS/MAPK pathway, have demonstrated some success (increased progression-free and overall survival) in patients with cancer, in particular colorectal cancer and NSCLC.


One of the most common somatic alterations in colon cancer and NSCLC is the presence of activating mutations in the protooncogene KRAS. KRAS is recruited by ligand-bound (active) EGFR to initiate the signaling cascade induced by the RAS/MAPK pathway. Because mutant KRAS constitutively activates the RAS/MAPK pathway downstream of EGFR, agents such as cetuximab and panitumumab, which prevent ligand-binding to EGFR, do not appear to have any meaningful inhibitor activity on cell proliferation in the presence of mutant KRAS. Current data suggest that the efficacy of EGFR-targeted therapies in colon cancer and NSCLC is confined to patients with tumors lacking KRAS mutations. An exception is the KRAS G12C mutation that is targetable with mutant-specific inhibitors.


This test uses DNA extracted from tumor tissue to evaluate for the presence of KRAS (G12A, G12C, G12D, G12R, G12S, G12V, G13D, Q61K, Q61L, Q61R, Q61H, and A146T) mutations. A positive result indicates the presence of an activating KRAS mutation and can be a useful marker by which patients are selected for EGFR-targeted therapy.

Reference Values
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

An interpretive report will be provided.

Provides information to assist in interpretation of the test results

An interpretative report will be provided.

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

Not all patients whose tumors have wild-type KRAS respond to epidermal growth factor receptor (EGFR)-targeted therapies.


Rare variants (ie, polymorphisms) exist that could lead to false-negative or false-positive results.


Test results should be interpreted in context of clinical findings, tumor sampling, and other laboratory data. If results obtained do not match other clinical or laboratory findings, contact the laboratory for possible interpretation. Misinterpretation of results may occur if the information provided is inaccurate or incomplete.


This assay was designed to detect mutations in KRAS codons 12, 13, 61, and 146 (G12A, G12C, G12D, G12R, G12S, G12V, G13D, Q61K, Q61L, Q61R, Q61H, and A146T).


This test has not been clinically validated for use as a tool to monitor response to therapy or for early detection of tumors.


This test cannot differentiate between somatic and germline alterations.

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

Yonkus JA, Alva-Ruiz R, Abdelrahman AM, et al: Molecular peritoneal staging for pancreatic ductal adenocarcinoma using mutant KRAS droplet-digital polymerase chain reaction: Results of a prospective clinical trial. J Am Coll Surg. 2021 Jul;233(1):73-80.e1. doi: 10.1016/j.jamcollsurg.2021.05.009

Special Instructions
Library of PDFs including pertinent information and forms related to the test

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

Digital droplet polymerase chain reaction is used to test for the presence of KRAS codon 12, 13, 61, and 146 mutations.(Unpublished Mayo method)

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


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.

8 to 12 days

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

Extracted DNA: 3 months

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


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 Regional Manager. 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 was developed, and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.

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.

81275-KRAS (v-Ki-ras2 Kirsten rat sarcoma viral oncogene) (eg, carcinoma) gene analysis, variants in codons 12 and 13

81276-KRAS (v-Ki-ras2 Kirsten rat sarcoma viral oncogene) (eg, carcinoma) gene analysis, additional variants

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
KRASW KRAS Mutation Analysis, Peritoneal 21702-6
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.
616453 Result Summary 50397-9
616454 Result 82939-0
616455 Interpretation 69047-9
616456 Specimen 31208-2
616457 Source 31208-2
616459 Released By 18771-6
616460 Method 85069-3
616461 Disclaimer 62364-5
616462 Additional Information 48767-8

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 | Create a 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