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HelpTest Code HMB45 HMB45 Immunostain, Technical Component Only
Reporting Name
HMB45 IHC, Tech OnlyUseful For
Identification of activated and neoplastic melanocytes
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)
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
TECHONLYOrdering 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 "Attention Pathology" address label (T498) and the pink Immunostain Technical Only label included in the kit to the outside of the transport container.
Specimen Required
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
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
CPT Code Information
88342-TC, primary
88341-TC, if additional IHC
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| HMB45 | HMB45 IHC, Tech Only | Order only;no result |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 70772 | HMB45 IHC, Tech Only | Bill only; no result |
Secondary ID
70459Clinical Information
The HMB45 immunostain identifies an antigen that is associated with a pre-melanosomal glycoprotein found in activated and neoplastic melanocytes. Most melanomas (approximately 90%) react with HMB45. HMB45 staining is cytoplasmic and is usually diffuse but may be focal. Benign nevi (moles) and other tumors that have melanin production (such as peripheral nerve sheath tumors) also stain positively.
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. 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.
Clinical Reference
1. Uguen A, Uguen M, Gujbourg B, Talagas M, Marcorelles P, De Braekeleer M. The p16-Ki-67-HMB45 immunohistochemistry scoring system is highly concordant with the fluorescent in situ hybridization test to differentiate between melanocytic nevi and melanomas. Appl Immunohistochem Mol Morphol. 2018;26(6):361-367. doi:10.1097/PAI.0000000000000428
2. Kriegsmann M, Kriegsmann M, Kriegsmann K, et al. Expression of HMB45, melanA and SOX10 is rare in non-small cell lung cancer. Diagn Pathol. 2018;13(1):68. doi:10.1186/s13000-018-0751-7
3. Garola R, Singh V: Utility of p16-Ki-67-HMB45 score in sorting benign from malignant Spitz tumors. Pathol Res Pract. 2019;215(10):152550. doi:10.1016/j.prp.2019.152550
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)
Report Available
1 to 3 daysSpecimen Retention Time
Until staining is complete.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.Forms
If not ordering electronically, complete, print, and send a Immunohistochemical (IHC)/In Situ Hybridization (ISH) Stains Request (T763) with the specimen.
Cautions
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