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HelpTest Code KRASW KRAS Somatic Mutation Analysis, Peritoneal Fluid
Shipping Instructions
Necessary Information
1. A pathology report (final or preliminary) is required and must accompany specimen for testing to be performed.
2. The following information must be included in the report provided.
-Patient name and second identifier
-Date of fluid collection
-Source of the fluid
Specimen Required
Container/Tube: 50-mL Falcon tube
Preferred: Fresh, peritoneal washing; no fixatives added to wash
Specimen Volume: Two 50-mL Falcon tubes
Collection Instructions: Containers must be labeled with two unique patient identifiers.
Useful For
Staging of the pancreatic ductal adenocarcinoma(1)
Disease States
- Colorectal cancer
Special Instructions
Method Name
Droplet Digital Polymerase Chain Reaction (ddPCR)
Reporting Name
KRAS Mutation Analysis, PeritonealSpecimen Type
PeritonealSpecimen Minimum Volume
100 mL of peritoneal washing
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Peritoneal | Refrigerated (preferred) | 10 days | |
| Ambient | 5 days |
Reject Due To
| Fixative added | Reject |
Clinical Information
Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy with predilection for peritoneal dissemination. Accurate peritoneal staging is important for management of patients with PDAC. The KRAS oncogene is the most frequently mutated oncogene in PDAC. Detection of KRAS mutations within peritoneal fluid has been associated with clinically positive laparoscopic findings (gross metastases and/or positive peritoneal cytology) and elevated peritoneal fluid carbohydrate antigen 19-9 and/or carcinoembryonic antigen and may portend an increased risk of residual/recurrent pancreatic cancer metastases within the peritoneal cavity.
This test uses DNA extracted from cells shed into the peritoneum 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 to aid in the staging of pancreatic ductal adenocarcinoma.
Reference Values
An interpretive report will be provided.
Interpretation
The interpretation of molecular biomarker analysis includes an overview of the results and the associated diagnostic, prognostic, and therapeutic implications.
Cautions
Patients with a negative test result may still harbor a KRAS mutation below the level of detection.
The limit of detection of this assay is influenced by the amount of cells and DNA in the peritoneal wash. This is a biological variable that cannot be controlled.
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.
Method Description
Droplet digital polymerase chain reaction is used to test for the presence of KRAS codon 12, 13, 61, and 146 mutations.(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;233[1]:73-80.e1. doi:10.1016/j.jamcollsurg.2021.05.009)
Day(s) Performed
Monday through Friday
Report Available
5 to 10 daysSpecimen Retention Time
Extracted DNA: 3 monthsPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
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 Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| KRASW | KRAS Mutation Analysis, Peritoneal | 21702-6 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 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 |