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UW Health SMPH
American Family Children's Hospital

UW Hospital and Clinics Lab Test Directory

Test Name: KRAS Mutation Detection, Tissue

Test Code(s): Orderable through Surgical Pathology

CPT Code(s): 81275

Methodology: Real-Time PCR and Pyrosequencing

Clinical Significance: KRAS mutations occur in 30-50% of colorectal adenocarcinomas and 10-30% of non-small cell lung carcinomas. This assay analyzes codons 12 and 13 in exon 1 and codon 61 in exon 2 of the KRAS gene; based on the current literature, approximately 98% of mutations are expected to occur in these codons.

Days Performed: Once a week.

Turnaround Time: Routine: 10 days.

Specimen Requirements

Specimen: Formalin-fixed, paraffin embedded tissue.

Collection Instructions: Please fill out Clinical Laboratories Referral Screening Flow Sheet if test is being added to specimen that was collected >30 days before add on order. Forms available on U-Connect under Documents-> Clinical Labs-> Forms (see hyperlink in Additional Information field to bridge to this form) or by calling UWHC Test Referral office at (608) 262-6388.  

Sample Analyzed: Tissue

Specimen Processing: Three slides each containing 5 microns (uM) of FFPE tissue should be sent. Second slide should be H&E stained with the tumor circled. Please indicate percent tumor on Intra-Lab Send-Out Form.

If an add-on order is needed, please contact UWHC Surgical Pathology at (608)263-8443. A Surgical Pathology Tissue Examination Request form will need to be completed and faxed to (608)262-7174.

Specimen Transport: Transport at room temperature.

Outreach Specimen Transport: Transport with a cold pack. Avoid excessive heat.

Stability: Ambient: Indefinitely.
Refrigerated: Indefinitely.
Frozen: Do not Freeze.


Expected result: Not detected. A written interpretive report is provided by the laboratory.

Test Limitations:

A "Not Detected" results may be the results of insufficient tissue or tumor present or may be due to the presence of PCR inhibitors. The detection limit is 10% mutated DNA in a non-mutated background.

Additional Information:

A "Detected" results indicates the presence of a Kras mutation. A "Not detected" result does not rule out the presence of a Kras mutation. Inadequate specimen collection, processing and storage may invalidate test results. This test should not be used as the only criterion to form a clinical conclusion, instead, results should be correlated with other test results, patient symptoms and clinical presentation. 


The performance characteristics of this test were validated by UWHC Clinical Laboratories. The U.S. Food and Drug Administration (FDA) has not approved or cleared this test; however, FDA approval or clearance is currently not required for clinical use of this test. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions. The UWHC Clinical Laboratories is authorized under Clinical Laboratory Improvement Amendments (CLIA) to perform high-complexity testing.


A professional fee is associated with this test.


Referral Screening Flow Sheet

K-RAS colorectal cancer tumor markers, kras, KRAS

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