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HelpTest Code SMACN Actin, Smooth Muscle (SMActin) 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
Forms
If not ordering electronically, complete, print, and send a Immunohistochemical (IHC)/In Situ Hybridization (ISH) Stains Request (T763) with the specimen.
Secondary ID
70551Useful For
Identification of cells expressing the alpha-smooth muscle isoform of actin
Reflex Tests
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| IHTOI | IHC Initial, Tech Only | No | No |
| IHTOA | IHC Additional, Tech Only | No | No |
Method Name
Immunohistochemistry (IHC)
Reporting Name
Actin, smooth muscle IHC, Tech OnlySpecimen Type
TECHONLYSpecimen 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
Smooth muscle actin reacts with the alpha-smooth muscle isoform of actin, and labels the smooth muscle cells of vessels, myoepithelial cells, pericytes, some stromal cells in the intestine, testis, and ovary, and tumors derived from smooth muscle cells. The antibody does not react with actin from fibroblasts, striated muscle, and myocardium. This immunostain is a useful tool in the identification of leiomyomas, leiomyosarcomas, and pleomorphic adenomas.
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; call 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. Arora G, Girdhar M, Gaghla A, et al. Comparing the expression of myoepithelial cell markers CD10 and smooth muscle actin with the estrogen receptor status in the invasive carcinoma breast: An immunohistochemical study. Clin Cancer Invest J. 2013;2:20-24
2. Nishio J, Iwasaki H, Skashita N, et al. Undifferentiated (embryonal) sarcoma of the liver in middle-aged adults: smooth muscle differentiation determined by immunohistochemistry and electron microscopy. Hum Pathol. 2003;34(3):246-252.
3. Tse GM, Tan PH, Lui PC, et al. The role of immunohistochemistry for smooth-muscle actin, p63, CD10 and cytokeratin 14 in the differential diagnosis of papillary lesions of the breast. J Clin Pathol. 2007;60(3):315-320
4. Magaki S, Hojat SA, Wei B, So A, Yong WH. An introduction to the performance of immunohistochemistry. Methods Mol Biol. 2019;1897:289-298. doi:10.1007/978-1-4939-8935-5_25
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 complete.Performing 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
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| SMACN | Actin, smooth muscle IHC, Tech Only | Order only;no result |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 70863 | Actin, smooth muscle IHC, Tech Only | Bill only; no result |
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).