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HelpTest Code MT Metallothionein 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.
Shipping Instructions
Attach the green pathology address label and the pink Immunostain Technical Only label included in the kit to the outside of the transport container.
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
Secondary ID
619972Useful For
Supporting the diagnosis of Wilson disease
Reflex Tests
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| IHTOI | IHC Initial, Tech Only | No | No |
| IHTOA | IHC Additional, Tech Only | No | No |
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).
Method Name
Immunohistochemistry (IHC)
Reporting Name
Metallothionein IHC, Tech OnlySpecimen Type
TECHONLYSpecimen Minimum Volume
See Specimen Required
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 |
Clinical Information
This test is intended to identify the presence of metallothionein (MT). MT is useful to support a diagnosis of Wilson disease (WD). MT plays a role in binding the accumulated copper in WD disorder. MT can detect even early-stage cases of WD before the development of cirrhosis. The MT assay has been shown to have higher sensitivity and specificity compared to the use of the Leipzig criteria and rhodanine. MT expression by IHC is a more cost effective and practical approach compared to quantitative liver copper assays.
Interpretation
This test does not include pathologist interpretation only technical performance of the stain. If interpretation is required order PATHC / Pathology Consultation for a full diagnostic evaluation or second opinion of the case.
The positive and negative controls are verified as showing appropriate immunoreactivity and documentation is retained at Mayo Clinic Rochester. If a control tissue is not included on the slide, a scanned image of the relevant quality control tissue is available upon request. Contact 855-516-8404.
Interpretation of this test should be performed in the context of the patient's clinical history and other diagnostic tests by a qualified pathologist.
Cautions
Age of a cut paraffin section can affect immunoreactivity. Stability thresholds vary widely among published literature and are antigen dependent. Best practice is for paraffin sections to be cut within 6 weeks.
The charge of glass slides can be affected by environmental factors and subsequently may alter slide staining. Sending unsuitable glass slides can result in inconsistent staining due to poor slide surface chemistry.
Best practices for storage of positively charged slides:
-Minimize time slides are stored after being unpackaged
-Limit exposure to high humidity and heat
-Minimize exposure to plastics
Clinical Reference
1. Rowan D, Mangalaparthi KK, Singh S, et al. Metallothionein immunohistochemistry has high sensitivity and specificity for detection of Wilson disease. Mod Pathol. 2022;35(7):946-955
2. Poujois A, Woimant F. Wilson's disease: A 2017 update. Clin Res Hepatol Gastroenterol. 2018;42(6):512-520
3. Mulder TP, Janssens AR, Verspaget HW, et al. Metallothionein concentration in the liver of patients with wilson's disease, primary biliary cirrhosis, and liver metastasis of colorectal cancer. J Hepatol. 1992;16(3):346-350
4. Petering DH, Fowler BA. Roles of metallothionein and related proteins in metal metabolism and toxicity: problems and perspectives. Environ Health Perspect. 1986;65:217-224
Method Description
Immunohistochemistry on sections of paraffin-embedded tissue.(Unpublished Mayo method)
Day(s) Performed
Monday through Friday
Report Available
1 to 3 daysSpecimen Retention Time
Until staining is completePerforming Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.CPT Code Information
88342-TC, primary
88341-TC, if additional IHC
LOINC Code Information
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 619973 | Metallothionein IHC, Tech Only | No LOINC Needed |
Forms
If not ordering electronically, complete, print, and send a Immunohistochemical (IHC)/In Situ Hybridization (ISH) Stains Request (T763) with the specimen.