Test Catalog

Test ID: CDKPB    
CD68 (KP1) Immunostain, Bone Marrow, Technical Component Only

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

Aiding in the identification of histocytic and myeloid lineage 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

In normal tissues, CD68 KP-1 stains the cytoplasm of the granulocytes and myeloid progenitors in the bone marrow, monocytes, and macrophages, and osteoclasts. KP-1 reacts against a carbohydrate moiety of CD68. Although CD68 KP-1 is primarily used as a histiocytic marker, it is not specific for histiocytes. It can also be expressed in malignant melanoma, granular cell tumors, peripheral nerve sheath tumors, malignant fibrous histiocytoma, and other mesenchymal neoplasms and rare carcinomas.

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 within 6 weeks.

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

1. Sanchez-Espiridion B, Martin-Moreno AM, Montalban C, et al: Immunohistochemical markers for tumor associated macrophages and survival in advanced classical Hodgkin's lymphoma. Haematologica 2012;97:1080-1084

2. Tan KL, Scott DW, Hong F, et al: Tumor-associated macrophages predict inferior outcomes in classic Hodgkin lymphoma. A Correlative Study from the E2496 Intergroup Trial. Blood 2012;120(18):3280-3287

3. Mehra N, Schnatiwinkel C, Ergon L, et al: Comparison of multiplexed imaging mass cytometry in FFPE tissue to monoplex immunohistochemistry. Tumor Biology 2018;78(13):3037