Orthopedia Homeobox Protein (OTP) Immunostain, Technical Component Only

Casandra

Casandra Test Code MC53080Version 1 (DRAFT)

Performing Lab

Lab Mayo Clinic LabLab Test ID OTPCPT Codes 88341, 88342

Orthopedia Homeobox Protein (OTP) Immunostain, Technical Component Only

Clinical Use

Use

This test is useful for distinguishing lung carcinoid tumors from metastatic neuroendocrine tumors. The orthopedia homeobox protein (OTP) is a nuclear transcription factor that 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 has been reported to have high sensitivity and specificity for diagnosing lung carcinoid tumors, while cytoplasmic granular staining does not reflect OTP expression and should not be regarded as positive.

Special Instructions

This test includes only the technical performance of the stain; no pathologist interpretation is provided. Technical component-only stains should not be ordered with PATHC / Pathology Consultation, as they will be canceled if ordered together. Shipping instructions specify the use of the green pathology address label and the pink Immunostain Technical Only label on the transport container.

Limitations

Age of a cut paraffin section can affect immunoreactivity. Stability thresholds vary among published literature and are antigen-dependent, with best practice being sections cut within 6 weeks. The charge of glass slides can be affected by environmental factors, potentially altering slide staining. Improper specimen collection and handling conditions, such as sending unsuitable glass slides, may result in inconsistent staining due to poor slide surface chemistry.

Test Details

New York Approved

Methodology

Immunoassay (IHC)

Biomarkers

Orthopedia Homeobox Protein (OTP)

Protein

IHC • Expression • Categorical (e.g., Positive / Negative / Indeterminate)

Result Turnaround Time

1-3 days

Specimen

Tissue (FFPE)

Volume

Not provided

Minimum Volume

Not provided

Container

Immunostain Technical Only Envelope

Collection Instructions

Please provide formalin-fixed, paraffin-embedded tissue block or 2 unstained, positively charged glass slides per test ordered. Each slide should be 25 x 75 x 1-mm, and sections should be 4-microns thick.