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HelpTest Code T790M Cell-Free DNA EGFR T790M Mutation Analysis, Blood
Reporting Name
cfDNA EGFR T790M Test, BloodUseful For
Determination of EGFR T790M mutation status in blood specimens as an alternative to invasive tissue biopsies
Identification of patients with non-small cell lung cancer who harbor a T790M mutation and may benefit from specific EGFR-targeted therapies
Method Name
Droplet Digital Polymerase Chain Reaction (ddPCR)
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
Whole bloodOrdering Guidance
This test is not a prenatal screening test.
This test detects only the T790M mutation in the EGFR gene. It does not detect other EGFR gene mutations in exons 18 through 21.
This test provides rapid detection of the EGFR T790M mutation in peripheral blood from non-small cell lung cancer patients as an alternative for EGFR analysis of tissue. For tissue testing, order EGFRS / EGFR Gene, Targeted Mutation Analysis, 51 Mutation Panel, Tumor.
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)
Specimen Volume: Two, 10-mL Streck cell-free DNA (cfDNA) blood collection tubes
Additional Information:
1. Only blood collected in Streck cfDNA tubes will be accepted for analysis.
2. Whole blood will be processed to produce platelet-poor plasma before cfDNA isolation.
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 |
Reject Due To
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.Reference Values
An interpretive report will be provided.
Day(s) Performed
Varies
CPT Code Information
81235
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| T790M | cfDNA EGFR T790M Test, Blood | 55769-4 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 113411 | Result Summary | 50397-9 |
| 113412 | Result | 55769-4 |
| 113413 | Interpretation | 69047-9 |
| 113414 | Additional Information | 48767-8 |
| 113415 | Specimen | 31208-2 |
| 113416 | Source | 31208-2 |
| 113417 | Released By | 18771-6 |
Secondary ID
113410Disease States
- Non-small cell lung cancer
Clinical Information
Epidermal growth factor receptor (EGFR)-targeted tyrosine kinase inhibitors (eg, gefitinib and erlotinib) have been approved by the US food and Drug Administration (FDA) for use in treating patients with non-small cell lung cancer (NSCLC) who previously failed to respond to traditional chemotherapy. However, the EGFR T790M mutation is associated with acquired resistance to tyrosine kinase inhibitor (TKI) therapy in about 60% of patients with disease progression after initial response to erlotinib, gefitinib, or afatinib. Recent data suggest that patients with metastatic NSCLC and the T790M mutation may benefit from osimertinib, an FDA-approved oral TKI that inhibits both EGFR-activating mutations and the T790M mutation.
Interpretation
The interpretation of molecular biomarker analysis includes an overview of the results and the associated therapeutic implications.
Cautions
Patients with a negative test result may still harbor the EGFR T790M mutation. Mutation testing of a tissue specimen for EGFR mutations should be considered for patients with a negative result with this test.
The limit of detection of this assay for the detection of EGFR mutations is influenced by the amount of cell-free DNA in the blood. This is a biological variable that cannot be controlled.
This assay was designed to detect the following T790M mutation in the EGFR gene.
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. Additional testing may be necessary to clarify the significance of results if there is a potential hereditary risk.
Clinical Reference
1. Schwarzenbach H, Hoon DSB, Pantel K: Cell-free nucleic acids as biomarkers in cancer patients. Nat Rev Cancer. 2011 Jun;11(6):426-437
2. Ettinger DS, Wood DE, Aisner DL, et al: Non-Small Cell Lung Cancer, Version 5.2017, NCCN Clinical Practice Guidelines in Oncology. J Natl Compr Canc Netw. 2017 Apr;15(4):504-535
3. Janne PA, Yang JCH, Kim DW, et al: AZD9291 in EGFR inhibitor-resistant non-small-cell lung cancer. N Engl J Med. 2015 Apr 30;372(18):1689-1699
Method Description
Blood samples are collected in Streck Cell-Free DNA BC Tubes. Cell-free DNA is isolated from double-centrifuged plasma and assessed for the presence of the EGFR T790M mutation using droplet digital polymerase chain reaction analysis.(Unpublished Mayo method)
Report Available
5 to 10 daysTest 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.Forms
If not ordering electronically, complete, print, and send an Oncology Test Request (T729) with the specimen.