Lynch Syndrome, MLH1 Sequencing and Deletion/Duplication

Test Code
91460


CPT Codes
81292, 81294

Includes
If "Result" is positive, cascading reflex to Path Variant, Variant 1, and VUS will be performed as needed.


Preferred Specimen
5 mL whole blood collected in an EDTA (lavender-top) tube or ACD (yellow-top) tube


Minimum Volume
2 mL whole blood


Other Acceptable Specimens
Saliva collected in the Oragene-Dx collection kit or
15 mL amniotic fluid collected in sterile container or
20 mg chorionic villus (CVS) tissue with 2-3 mL of sterile saline or tissue culture medium collected in sterile container or
Cultured cells in 2 T-25 flasks with 80-100% confluent growth or
Skin fibroblasts collected in sterile plastic container

For amniotic fluid, chorionic villus (CVS), and skin fibroblasts, call 1-866-GENEINFO (1-866-436-3463) prior to collecting and ordering.


Instructions
Saliva: 2 mL saliva collected in the Oragene-Dx collection kit up to the “fill to" line (OGD-500/OGD-600, OGD-510/OGD-610). Do NOT eat, drink, smoke or chew gum for 30 minutes before collection. Do NOT remove the plastic film from the funnel lid. Once sample is collected, tighten the cap on the tube. Please follow included instructions for use.
For amniotic fluid, chorionic villus (CVS), and skin fibroblasts: Call 1-866-GENEINFO (1-866-436-3463) prior to collecting and ordering.


Transport Container
EDTA (lavender-top) tube or ACD (yellow-top) tube


Transport Temperature
Room temperature


Specimen Stability
Whole blood
Room temperature: 14 days
Refrigerated: 14 days
Frozen: Unacceptable

Saliva
Room temperature: 14 days
Refrigerated: 14 days
Frozen: 14 days

Amniotic fluid (AF), chorionic villus (CVS), skin fibroblasts
Room temperature: 48 hours
Refrigerated: Unacceptable
Frozen: Unacceptable


Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Clotted whole blood


Methodology
DNA Bait Capture • Long Range Polymerase Chain Reaction • Next Generation Sequencing • Microarray

FDA Status
This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by the FDA. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.

Setup Schedule
Set up: Tues, Thurs, Sat; Report available: 14-21 days from completed pre-authorization


Reference Range
See Laboratory Report


Clinical Significance
Sequencing: This test should be offered to patients with colorectal cancer who meet the Bethesda criteria established by the National Cancer Institute (NCI), and/or that their tumors display microsatellite instability (MSI) or replication error (RER) phenotype. Detection of a germline mutation in one or the mismatch repair genes helps to establish a clinical diagnosis of HNPCC in affected patients. Mutation detection in at risk family member allows predictive diagnosis of the disease and thus intensive screening and early intervention of cancer.
Deletion/Duplication: This assay detects deletions and/or duplication involving one or more exons, as well as the entire MLH1 gene. This assay cannot detect smaller genetic alterations, such as point mutations affecting amino acid coding or mRNA splicing. The assay cannot detect mutations affecting MLH1 gene regions not examined in the assay (including most of the intronic regions). This assay cannot rule out the presence of germline mutations involving other mismatch repair genes.


Performing Laboratory
Quest Diagnostics Nichols Institute-San Juan Capistrano, CA
33608 Ortega Highway
San Juan Capistrano, CA 92675-2042




The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.