Immunohistology is essential to the practice of modern surgical and cytopathology. There are 3 major types of immunohistologic services provided in clinical practice: traditional immunohistochemistry, morphometric analysis of tumor immunohistochemistry, and immunofluorescence. Proper Current Procedural Terminology coding for these services has been updated to reflect current medical practice. Subsequent to changes in the Current Procedural Terminology coding structure for these services, the valuation of these services have been reviewed by the American Medical Association/Specialty Society Relative Value Update Committee and new valuations instituted by the Centers for Medicare and Medicaid Services. Although valuations for services may be established, the circumstances of payment may be affected by Medicare Contractor’s Local Coverage Determinations or service limits imposed by the National Correct Coding Initiative.