Thyroid Transcription Factor-1, IHC with Interpretation [19278X]

Test Code

CPT Codes

Preferred Specimen
Formalin-fixed, paraffin-embedded tissue block

Other Acceptable Specimens
Minimum: 3 unstained, positively charged slides

Please include surgical pathology report

Transport Container
IHC Specimen Transport Kit

Transport Temperature
Room temperature

Specimen Stability
Room temperature: Indefinitely
Refrigerated: Indefinitely
Frozen: Unacceptable


Setup Schedule
Set up: Mon-Fri; Report available: 2 days

Reference Range
See Laboratory Report

Clinical Significance

This immunoassay is often used to evaluate neoplasms of unknown origin and assist in characterizing whether the neoplasm was derived from a pulmonary or thyroid lineage [1].

Thyroid transcription factor 1 (TTF-1) is a nuclear protein that is expressed in certain lung, thyroid, and diencephalon cells. Papillary, follicular, and medullary thyroid carcinomas are generally immunoreactive with TTF-1 antibodies. Approximately 75% of nonmucinous primary pulmonary adenocarcinomas and 90% of primary pulmonary small cell carcinomas are immunoreactive with TTF-1 antibodies. Primary pulmonary squamous cell carcinomas and mesotheliomas are generally non-reactive with TTF-1 antibodies. Likewise, dermal Merkel cell carcinomas are generally non-reactive with TTF-1 [1].

A small percentage of primary pulmonary squamous cell carcinomas stain positively with TTF-1. In addition, certain gynecologic tumors and small cell carcinomas of urothelial origin may express TTF-1 [1].

The results of this test should be interpreted in the context of pertinent clinical and family history as well as physical examination findings.

1. Rekhtman N, et al. Quick Reference Handbook for Surgical Pathologists. 2nd ed. Springer; 2019:3-37, 64, 79.

Performing Laboratory
Quest Diagnostics Nichols Institute
14225 Newbrook Drive
Chantilly, VA 20153

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.