Days Set Up
Monday - Friday
Analytic Time

3 - 10 days

MiChart Code
Germline MLH1 Promotor Methylation
Soft Order Code

Test Updated:


Hereditary Nonpolyposis Colorectal Cancer (HNPCC)
Lynch Syndrome

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Test Overview

Test Methodology

Methylation-specific real-time PCR

Test Usage

Hereditary nonpolyposis colorectal cancer (HNPCC), also known as Lynch Syndrome, is an autosomal dominant condition associated with increased risk of multiple cancers particularly colorectal and endometrial. This syndrome most commonly results from mutations of genes encoding DNA mismatch repair proteins including MLH1, MSH2, MSH6 and PMS2. These mutations lead to tumors with microsatellite instability (MSI) – a change in length of a microsatellite allele due to either insertion or deletion of repeating units. MSI can also occur in sporadic colorectal, endometrial and other cancers in patients without HNPCC. In sporadic cancers, MSI is typically associated with silenced MLH1 protein expression resulting from somatic hypermethylation of the MLH1 promoter. However, constitutional epimutations that result in germline MLH1 promoter hypermethylation also exist. Germline MLH1 promoter hypermethylation may confer an HNPCC (Lynch) syndrome phenotype even in the absence of primary sequence alternations in the MLH1 gene. Germline MLH1 promoter methylation can be documented by detecting methylation in non-neoplastic tissue (peripheral blood). Genetic counseling may be indicated based on the clinical and laboratory findings

Please note this “Germline MLH1 Promoter Methylation” test is a distinct orderable and has a different indication than the standard “MLH1 Promoter Methylation” test. The Germline MLH1 Promoter Methylation test is used to evaluate for constitutional MLH1 promoter methylation in peripheral blood specimens. The standard MLH1 Promoter Methylation test is used to evaluate for MLH1 promoter methylation in tumor specimens from formalin-fixed paraffin-embedded tissue blocks.

Reference Range

Interpretive report provided.

* Reference ranges may change over time. Please refer to the original patient report when evaluating results.

Specimen Requirements

Collection Offsite

Collect blood in a lavender top tube. Refrigerate and send intact blood or bone marrow specimen within 24 hours of collection.

Lavender Top Tube
Normal Volume
6 mL EDTA whole blood. Extracted DNA is also acceptable if extracted in a CLIA certified laboratory.
Minimum Volume
3 mL EDTA whole blood

Billing Information

CPT Code
Pro Fee Code

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Our High Standard

Quality that sets us apart

As the reference laboratory division of Michigan Medicine's Department of Pathology, MLabs shares the institution's commitment to applying established quality principles to clinical laboratory testing. Like other large organizations in complex, consequential fields, we rely on an established approach to monitor quality throughout the testing process.