Sign in →

Test ID: KRASD Cell-Free DNA KRAS 12, 13, 61,146, Blood

Advisory Information

This test is not a prenatal screening test. To evaluate for the presence of common fetal chromosome abnormalities using cell-free DNA, order NIPS / Cell-Free DNA Prenatal Screen.

Shipping Instructions

1. Samples should be transported at ambient temperature or refrigerated (4° C).

2. Samples are viable for 7 days in the Streck Black/Tan Top Tube Kit (T715).

Specimen Required

Supplies: Streck Black/Tan Top Tube Kit (T715)

Container/Tube: Streck Cell-Free DNA blood collection kit (T715)

Specimen Volume: Two 10-mL Streck Cell-Free DNA blood collection tubes

Additional Information: Only blood collected in Streck Cell-Free DNA BCT tubes will be accepted for analysis. Whole blood will be processed to produce platelet-poor plasma before cfDNA isolation.

Useful For

As an alternative to invasive tissue biopsies for the determination of KRAS 12, 13, 61,146 (G12A, G12C, G12D, G12R, G12S, G12V, G13D, Q61K, Q61L, Q61R, Q61H, and A146T) mutation status


Selection of patients with colorectal cancer who are most likely to benefit from epidermal growth factor receptor (EGFR)-targeted therapies

Method Name

Digital Droplet Polymerase Chain Reaction (PCR)

Reporting Name

cfDNA KRAS 12, 13, 61, 146 Blood

Specimen Type

Whole blood

Specimen Minimum Volume

One 10 mL Streck tube

Specimen Stability Information

Specimen Type Temperature Time Special Container
Whole blood Ambient (preferred) 7 days Streck Black/Tan top
  Refrigerated  7 days Streck Black/Tan top

Clinical Information

Approximately 30% to 50% of colorectal cancers (CRC) have mutations in KRAS. Most occur in hotspot regions in codons 12, 13, 61, and 146. These mutations lead to constitutive activation of the RAS/MAPK pathway downstream of epidermal growth factor receptor (EGFR), limiting the effectiveness of anti-EGFR therapies, such as cetuximab and panitumumab, which inhibit ligand-mediated activation of EGFR. Therefore, identification and quantitation of these mutations is critical in selecting the appropriate therapy.


This test uses DNA extracted from peripheral blood 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 may be useful for guiding the treatment of individuals with colorectal cancer.


An interpretive report will be provided.

Clinical Reference

1. Schwarzenbach H, Hoon DS, Pantel K: Cell-free nucleic acids as biomarkers in cancer patients. Nat Rev Cancer 2011;11(6):426-437

2. Allegra CJ, Rumble BR, Hamilton SR, et al: Extended RAS Gene Mutation Testing in Metastatic Colorectal Carcinoma to Predict Response to Anti-Epodermal Growth Factor Receptor Monoclonal Antibody Therapy: ASCO Provisional Clinical Opinion update 2015. J Clin Oncol 2016 Jan 10;34(2):179-185

3. Olmedillas Lopez S, Garcia-Olmo DC, Garcia-Arranz M, et al: KRAS G12V Mutation Detection by Droplet Digital PCR in Circulating Cell-Free DNA of Colorectal Cancer Patients. Int J Mol Sci 2016;17:484

Day(s) and Time(s) Performed

 Monday through Friday; Varies

Analytic Time

5 days

Test Classification

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 U.S. Food and Drug Administration.

CPT Code Information



LOINC Code Information

Test ID Test Order Name Order LOINC Value
KRASD cfDNA KRAS 12, 13, 61, 146 Blood In Process


Result ID Test Result Name Result LOINC Value
113123 Result Summary 50397-9
113508 Result 75974-6
113125 Interpretation 69047-9
113126 Additional Information 48767-8
113127 Specimen 31208-2
113128 Source 31208-2
113129 Released By 18771-6


If not ordering electronically, complete, print, and send an Oncology Test Request (T729) with the specimen.

Mayo Clinic Laboratories | Gastroenterology Catalog Additional Information: