MLH1 Hypermethylation Analysis, Blood
Use
The MLH1 Hypermethylation Analysis, Blood test is used as an adjunct to positive hypermethylation in tumors to distinguish between somatic and germline hypermethylation. It is also used in cases where colon or endometrial tumors demonstrate microsatellite instability-H (MSI-H) and loss of MLH1 protein expression, especially when germline testing is negative. This supports the diagnosis of Lynch syndrome, an autosomal dominant hereditary cancer syndrome associated with germline variants in mismatch repair (MMR) genes and increased risks for colorectal and endometrial cancers.
Special Instructions
In cases of patients with previous bone marrow transplants from allogenic donors, the test may be interfered with, and special instructions are available at the provided contact. Also, postnatal umbilical cord whole blood specimens necessitate maternal cell contamination studies, requiring separate maternal blood specimen orders.
Limitations
Errors in test interpretation can occur with inaccurate or incomplete patient information, and the test results should be considered alongside clinical findings, family history, and other laboratory data. The presence of hypermethylation does not distinguish between somatic and germline origins without additional clinical context, possibly requiring further genetic evaluation for comprehensive assessment.
New York Approved
Methodology
PCR-based (PCR)
Biomarkers
LOINC Codes
- 97760-3
- 50397-9
- 82939-0
- 69047-9
- 42349-1
- 31208-2
- 18771-6
Result Turnaround Time
8-12 days
Related Documents
For more information, please review the documents below
Specimen
Whole Blood
Volume
3 mL
Minimum Volume
Not provided
Container
Lavender top (EDTA) or yellow top (ACD)
Collection Instructions
Invert several times to mix blood. Send whole blood specimen in original tube. Do not aliquot. Whole blood collected postnatal from an umbilical cord is also acceptable. See Additional Information for details.
Patient Preparation
A previous bone marrow transplant from an allogenic donor will interfere with testing. Call 800-533-1710 for instructions for testing patients who have received a bone marrow transplant.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 4 days |
| Refrigerated | 4 days |
| Frozen | 4 days |