Test Catalog

Test ID: CALD    
Caldesmon Immunostain, Technical Component Only

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

A marker of smooth muscle differentiation

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

Caldesmon is a smooth muscle specific protein that regulates smooth muscle contraction. This clone recognizes the high-molecular-weight variant (h-caldesmon) and does not react with the nonmuscle variant. Neither variant of caldesmon is present in skeletal muscle. Anti-h-caldesmon seems to be a reliable marker of smooth muscle differentiation, and may assist in the diagnosis of smooth muscle tumors.

Interpretation Provides information to assist in interpretation of the test results

This test does not include pathologist interpretation; only technical performance of the stain. If 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. 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. Wick MR, Hornick JL: Immunohistology of soft tissue and osseous neoplasms. In: Dabbs DJ, ed. Diagnostic Immunohistochemistry: Theranostic and Genomic Applications. 3rd ed. 2010:chap 4 2. Horita A, Kurata A, Maeda D,Fukayama M, Sakamoto A: Immunohistochemical characteristics of atypical polypoid adenomyoma with special reference to h-caldesmon. Int J Gynecol Pathol 2011 Jan;30(1)64-70

3. Ordonez NG: Value of PAX8, PAX2, claudin-4, and h-caldesmon immunostaining in distinguishing peritoneal epithelioid mesotheliomas from serous carcinomas. Modern Pathology. 2013;26:553-562