Test Catalog

Test ID: CD7    
CD7 Immunostain, Technical Component Only

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

Identification of T cells and natural killer cells

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

Cluster of differentiation 7 (CD7) is expressed normally on all T cells and natural killer cells. Expression of CD7 can be aberrantly lost in T-cell lymphomas, providing support for a diagnosis of T-cell lymphoma.

Interpretation Provides information to assist in interpretation of the test results

This test does not include pathologist interpretation; only technical performance of the stain is performed. If an 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, 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. Chu PG, Arber DA, Weiss LM: Expression of T/NK-cell and plasma cell antigens in non hematopoietic epithelioid neoplasms. An Immunohistochemical Study of 447 Cases. Am J Clin Pathol 2003;120:64-70

2. Dunphy CH: Applications of flow cytometry and immunohistochemistry to diagnostic hematopathology. Arch Pathol Lab Med 2004;128:1004-1022

3. Higgins RA, Blankenship JE, Kinney MC: Application of immunohistochemistry in the diagnosis of non-Hodgkin and Hodgkin lymphoma. Archives of Pathology and Laboratory Medicine 2008;132(3):441-461