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Test Code MLH1 MLH1 Immunostain, Technical Component Only


Ordering Guidance


This test includes only technical performance of the stain (no pathologist interpretation is performed). If diagnostic consultation by a pathologist is required order PATHC / Pathology Consultation.

 

This test can be ordered to help identify the responsible gene in DNA mismatch repair (MMR) within the tumor tissue.

 

For testing to help distinguish between a sporadic and germline etiology, order ML1HM / MLH1 Hypermethylation Analysis, Tumor.



Shipping Instructions


Attach the green "Attention Pathology" address label (T498) and the pink Immunostain Technical Only label included in the kit to the outside of the transport container.



Necessary Information


If sending normal and tumor blocks; indicate the block number to be stained in performing lab notes (electronic orders) or on the enclosed paperwork (manual orders).



Specimen Required


Specimen Type: Tissue

Supplies: Immunostain Technical Only Envelope (T693)

Container/Tube: Immunostain Technical Only Envelope

Preferred:

-Formalin-fixed, paraffin-embedded tissue block

OR

-2 Unstained, positively charged glass slides (25- x 75- x 1-mm) per test ordered; sections 4-microns thick

Acceptable: None


Useful For

Evaluation of tumor tissue to identify patients at high risk for having hereditary nonpolyposis colorectal cancer, also known as Lynch syndrome

 

Evaluation of tumor tissue to identify patients at risk for having hereditary endometrial carcinoma

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
IHTOI IHC Initial, Tech Only No No
IHTOA IHC Additional, Tech Only No No

Reporting Name

MLH1 IHC, Tech Only

Specimen Type

TECHONLY

Specimen Stability Information

Specimen Type Temperature Time Special Container
TECHONLY Ambient (preferred)
  Refrigerated 

Reject Due To

Wet/frozen tissue 
Cytology smears 
Nonformalin fixed tissue 
Nonparaffin embedded tissue 
Noncharged slides 
ProbeOn slides 
Snowcoat slides 		 Reject 

Day(s) Performed

Monday through Friday

Report Available

1 to 3 days

Specimen Retention Time

Until staining is complete.

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

88342-TC, primary

88341-TC, if additional IHC

LOINC Code Information

Test ID Test Order Name Order LOINC Value
MLH1 MLH1 IHC, Tech Only Order only;no result

 

Result ID Test Result Name Result LOINC Value
70822 MLH1 IHC, Tech Only Bill only; no result

Forms

If not ordering electronically, complete, print, and send a Immunohistochemical (IHC)/In Situ Hybridization (ISH) Stains Request (T763) with the specimen.

Testing Algorithm

For the initial technical component only immunohistochemical (IHC) stain performed, the appropriate bill-only test ID will be reflexed and charged (IHTOI). For each additional technical component only IHC stain performed, an additional bill-only test ID will be reflexed and charged (IHTOA).