Retinoblastoma Protein (Rb) Immunostain, Tech Only

Casandra

Casandra Test Code MC36292Version 1 (DRAFT)

Performing Lab

Lab Mayo Clinic LabLab Test ID RB1CPT Codes 88341, 88342

Retinoblastoma Protein (Rb) Immunostain, Tech Only

Clinical Use

Use

This test is useful for aiding in the identification of high-grade neuroendocrine carcinomas and small cell carcinomas. Retinoblastoma (Rb) is a phosphoprotein that acts as a tumor suppressor by providing a cell cycle checkpoint between G1 and S phases. Loss of nuclear expression of Rb can identify neuroendocrine carcinomas, small cell carcinomas, and can help differentiate spindle cell lipomas from myofibroblastomas and cellular angiofibromas from other genital stromal lesions.

Special Instructions

This test includes only the technical performance of the stain without pathologist interpretation. Technical component only stains should not be ordered with a pathology consultation (PATHC) as they will be canceled in such cases. For visual access, digital images of immunohistochemical stains are accessible online, or through electronic orders. Ensure correct labeling of transport container with 'Attention Pathology' and 'Immunostain Technical Only' labels.

Limitations

This test does not include pathologist interpretation, only the technical performance of the stain. The age of a cut paraffin section can affect immunoreactivity and antigen stability, influenced by environmental conditions such as humidity and heat. Use fresh sections for optimal results and store glass slides properly to maintain staining integrity. Minimize exposure to environmental factors that can affect slide quality, such as humidity, heat, and plastics.

Test Details

FDA Approved