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HelpTest Code MGMTD MGMT Promoter Methylation Analysis, Tumor
Necessary Information
A pathology report (final or preliminary), containing the following information, is required and must accompany specimen for testing to be performed:
1. Patient name
2. Block number-must be on all blocks, slides, and paperwork (can be handwritten on the paperwork)
3. Tissue collection date
4. Source of the tissue
Specimen Required
This assay requires at least 20% tumor nuclei.
-Preferred amount of tumor area with sufficient percent tumor nuclei: tissue 144 mm(2) tissue (4 x 6 mm x 6 mm areas)
-Minimum amount of tumor area: 36 mm(2) tissue (1 x 6 mm x 6 mm area)
-These amounts are cumulative over up to 10 unstained slides and must have adequate percent tumor nuclei.
-Tissue fixation: formalin-fixed paraffin-embedded (FFPE), non-decalcified
Submit only 1 of the following specimens:
Specimen Type: Tissue block
Collection Instructions: Submit a formalin-fixed non-decalcified, paraffin-embedded tissue block.
Specimen Type: Tissue slide
Slides: 1 Stained and 10 unstained
Collection Instructions: Submit 1 slide stained with hematoxylin and eosin and 10 unstained, nonbaked slides with 5-micron thick sections of the tumor tissue.
Note: The total amount of required tumor nuclei can be obtained by scraping up to 10 slides from the same block.
Useful For
Prognostication of newly diagnosed patients with glioblastoma
Identification of newly diagnosed glioblastoma patients that may derive benefit from alkylating chemotherapy (ie, temozolomide)
Therapy selection for newly diagnosed glioblastoma in older patients (>60-65 years)
Additional Tests
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| SLIRV | Slide Review in MG | No, (Bill Only) | Yes |
Testing Algorithm
When this test is ordered, slide review will always be performed at an additional charge.
Reporting Name
MGMT Promoter Methylation AnalysisSpecimen Type
VariesSpecimen Minimum Volume
5 unstained slides at 5-microns thickness
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Varies | Ambient (preferred) | |
| Refrigerated | ||
Reject Due To
| Specimens that have been decalcified (all methods) Specimens that have not been formalin-fixed, paraffin-embedded Extracted nucleic acid (DNA/RNA) |
Reject |
Reference Values
An interpretive report will be provided.
Supportive Data
Analytical validation studies demonstrated limit of quantitation for the assay to be 25 methylated copies. Fraction abundance (FA) threshold of 6.50% was above the estimated upper confidence interval limit of the 95th% quantile of the 95% confidence interval of values for non-neoplastic brain tissue. Clinical validation studies showed that this FA threshold favored identifying both low and high levels of methylation as positive for increased levels of methylation/"methylated" status, so that a negative result is more likely to indicate a truly negative result for increased levels of methylation/"unmethylated" status. Both values for methylated copies and FA will be used to determine if a sample is positive or negative for increased MGMT promoter methylation. A minimum of 360 unmethylated copies is required for a sample to be confidently resulted as negative.
Concordance between this test and the prior Mayo Clinic methylation-specific polymerase chain reaction and methylation array methods for detection of MGMT promoter methylation were 95% (194/205) and 97% (38/39), respectively.
The minimum viable tumor percent and DNA input required for testing are 20% and 25 ng, respectively.
Day(s) Performed
Varies
Report Available
7 to 10 daysSpecimen Retention Time
FFPE tissue block: Unused portions of blocks will be returned. Unused slides are stored indefinitely and not returned; Digital images are obtained and stored for all slides used in testing.Performing Laboratory
Mayo Clinic Laboratories in Rochester
CPT Code Information
81287
88381-Microdissection manual
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| MGMTD | MGMT Promoter Methylation Analysis | 60252-4 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 621859 | Result Summary | 50397-9 |
| 621860 | Result | 60252-4 |
| 621861 | Interpretation | 69047-9 |
| 621862 | Additional Information | 48767-8 |
| 621863 | Specimen | 31208-2 |
| 621864 | Source | 31208-2 |
| 621865 | Tissue ID | 80398-1 |
| 621866 | Method | 85069-3 |
| 621867 | Disclaimer | 62364-5 |
| 621868 | Released by | 18771-6 |