Test Catalog

Test ID: TPIT    
T-PIT Immunostain, Technical Component Only

Useful For Suggests clinical disorders or settings where the test may be helpful

Diagnosis of corticotroph, silent corticotroph, and null cell adenomas of the pituitary

Testing Algorithm Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

T-PIT is the transcription factor of functioning and silent corticotroph adenomas and is useful for the diagnosis of corticotroph adenoma and null cell adenoma. T-PIT may be included as part of a panel along with transcription factors SF-1 and Pit-1 to identify null cell adenomas (all negative).

Interpretation Provides information to assist in interpretation of the test results

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.


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.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

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.

Clinical Reference Recommendations for in-depth reading of a clinical nature

1. Jastania R, Alsaad K, Al-Shraim M, et al: Double adenomas of the pituitary: transcription factors Pit-1, T-pit, and SF-1 identify cytogenesis and differentiation. Endocr Pathol 2005;16(3):187-194

2. Casar-Borota O, Bollerslev J, Ponten F: Immunohistochemistry for transcription factor T-Pit as a tool in diagnostics of corticotroph pituitary tumours. Pituitary 2018;21:443

3. Sjostedt E, Bollerslev J, Mulder J, et al:  A specific antibody to detect transcription factor T-Pit: a reliable marker of corticotroph cell differentiation and a tool to improve the classification of pituitary neuroendocrine tumours.  Acta Neuropathol 2017;134:675-677

4. Drummond J, Roncaroli F, Grossman A, Korbonits M: Clinical and pathological aspects of silent pituitary adenomas. J Clin Endocrinol Metab 2019;104(7):2473-2489