Test Catalog

Test ID: HG34W    
Histone 3.3 G34W (H3F3A G34W) Immunostain, Tech Only

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

Aids in the diagnosis of giant cell tumor of bone (GCTB)

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

For the initial technical component only immunohistochemical (IHC) stain performed, the appropriate bill-only test ID will be reflexed and charged (IHTOI). For each additional technical component only IHC stain performed, an additional bill-only test ID will be reflexed and charged (IHTOA).

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

This test is intended to identify the presence of histone H3 G34W (H3F3A G34W). Giant cell tumors of bone (GCTB) are generally benign tumors characterized by mononuclear stromal cells and osteoclast-like giant cells. Up to 95% of GCTB have H3F3A gene mutation.

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. 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. Cleven A, Hocker S, Briaire-de Bruijn I, et al: Mutation Analysis of H3F3A and H3F3B as a Diagnostic Tool for Giant Cell Tumor of Bone and Chondroblastoma. Am J Surg Pathol 2015;39(11):1576-1583

2. Fernanda A, Bersha F, Ye H, et al: H3F3A (Histone 3.3) G34W Immunohistochemistry A Reliable Marker Defining Benign and Malignant Giant Cell Tumor of Bone. Am J Surg Pathol 2017;41(8):1059-1068

3. Luke J, Von Baer A, Schreiber J, et al: H3F3A mutation in giant cell tumour of the bone is detected by immunohistochemistry using a monoclonal antibody against the G34W mutated site of histone H3/3 variant. Histopath 2017;71(4):125-133

4. Yamamoto H, Iwasaki T, Yuichi Y, et al: Diagnostic Utility of Histone H3.3 G34W, G34R, and G34V Mutant-Specific Antibodies for Giant Cell Tumors of Bone. Human Pathol 2018;73(3):41-50