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Test Code OTP Orthopedia Homeobox Protein (OTP) 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

620710

Useful For

Distinguishing lung carcinoid tumors from metastatic neuroendocrine tumors

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

OTP IHC, Tech Only

Specimen Type

TECHONLY

Specimen 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

Orthopedia homeobox protein (OTP) is a nuclear transcription factor which may serve as a novel prognostic factor associated with pulmonary carcinoid tumors. Negative or weak expression of OTP is associated with poor prognosis. Nuclear staining for OTP is reported to have high sensitivity and specificity for the diagnosis of lung carcinoid tumors. Cytoplasmic granular staining does not reflect OTP expression and should not be regarded as positive.

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. Moonen L, Derks J, Dingemans AM, Speel EJ, Al. Orthopedia homeobox (OTP) in pulmonary neuroendocrine tumors: The diagnostic value and possible molecular interactions. Cancers. 2019;11(10),1508

2. Viswanathan K, Borczuk AC, Siddiqui MT, Orthopedia homebox protein (OTP) is a sensitive and specific marker for primary pulmonary carcinoid tumors in cytologic and surgical specimens. J Am Soc Cytopathol. 2019;8(1):39-46

3. Hanley KZ, Dureau ZJ, Cohen C, et al. Orthopedia homeobox is preferentially expressed in typical carcinoids of the lung. Cancer Cytopathol. 2018;126(4):236-242

Method Description

Immunohistochemistry on sections of paraffin-embedded tissue.(Unpublished Mayo method)

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

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
620711 OTP IHC, Tech Only No LOINC Needed