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

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 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. Ceballos KM, Nielsen GP, Selig MK, et al: Is anti-h-caldesmon useful for distinguishing smooth muscle and myofibroblastic tumors? An immunohistochemical study. Am J Clin Pathol 2000;114:746-753

2. Hisaoka M, Wei-Qi S, Jian W, et al: Specific but variable expression of h-caldesmon in leiomyosarcomas: an immunohistochemical reassessment of a novel myogenic marker. Appl Immunohistochem Mol Morphol 2001;9(4):302-308

3. Sakamoto A, Oda Y, Yamamota H, et al: Calponin and h-caldesmon expression in atypical fibrozanthoma and superficial leiomyosarcoma. Virchows Arch 2002;440:404-409