Test Catalog

Test ID: PRLI    
Prolactin (PRL) Immunostain, Technical Component Only

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

Subclassification of pituitary adenomas

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

Prolactin is a pituitary hormone involved in the stimulation of milk production, salt and water regulation, growth, development, and reproduction. Prolactin-producing cells constitute approximately 20% of the cells of the normal anterior pituitary. Antibodies to prolactin are used in a panel to subclassify pituitary adenomas.

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). Mayo Clinic cannot provide an interpretation of tech only stains outside the context of a pathology consultation. If an interpretation is needed, refer to PATHC / Pathology Consultation for a full diagnostic evaluation or second opinion of the case. All material associated with the case is required. Additional specific stains may be requested as part of the pathology consultation, and will be performed as necessary at the discretion of the Mayo pathologist.


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 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 fresh.

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

1. Ezzat S, Asa SL, Couldwell WT, et al: The prevalence of pituitary adenomas. A sytematic review. Cancer 2004;101:613-619

2. Hamid Z, Mrak RE, Ijaz M, Faas FH: Sensitivity and specificity of immunohistochemistry in pituitary adenomas. The Endocrinologist 2009;19:38-43

3. Osamura RY, Kajiva H, Takei M, et al: Pathology of the human pituitary adenomas. Histochem Cell Biol 2008;130(3):495-507

4. Zada G, Woodmansee WW, Ramkissoon R, et al: Atypical pituitary adenomas: incidence, clinical characteristics, and implications. J Neurosurg 2011;114:336-344