Summary & Overview
CPT 88369: Additional In Situ Hybridization Single Probe Stain and Evaluation
CPT code 88369 represents an additional in situ hybridization (ISH) single probe stain performed on slide(s) from the same patient specimen as an initial ISH probe stain, followed by professional evaluation by a qualified provider, usually a pathologist. This code captures supplemental laboratory staining and manual assessment activity that can be critical for precise tumor characterization and targeted therapy decisions. Nationally, appropriate coding and documentation for additional ISH stains affect diagnostic accuracy, clinical decision-making, and how pathology services are accounted for in payment systems.
Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will learn how 88369 is defined and applied in clinical workflows, the typical sites of service where it occurs, and the clinical context in which additional ISH single probe stains are ordered. The publication outlines common billing modifiers and billing considerations (list provided separately), summarizes typical use cases in tumor tissue evaluation, and highlights where data is not available in the input. This report provides concise benchmarks and policy-relevant context for coding teams, laboratory managers, and payers seeking clarity on the role and billing of additional ISH single probe staining and interpretation.
Billing Code Overview
CPT code 88369 describes an additional in situ hybridization (ISH) single probe stain applied to slide(s) prepared from the same patient specimen as an initial probe stain, such as tumor tissue. A qualified provider, typically a pathologist, evaluates the additionally stained slide(s), including manual counting or estimating the number and location of probes.
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Service type: Pathology laboratory additional ISH single probe staining and pathologist interpretation
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Typical site of service: Hospital pathology laboratory or independent clinical diagnostic laboratory
Clinical & Coding Specifications
Clinical Context
A 62-year-old patient with a recently resected breast mass undergoes molecular testing to evaluate HER2 gene amplification. The surgical pathology laboratory prepares formalin-fixed, paraffin-embedded tumor tissue sections and performs an initial in situ hybridization (ISH) single-probe stain. A lab technologist applies an additional ISH single probe stain (88369) to other slides from the same specimen to evaluate a different gene target or confirm results. A board-certified pathologist reviews the stained slides under a microscope, manually counts or estimates probe signals within tumor cell nuclei, documents the findings in the pathology report, and issues an interpretation that informs targeted therapy decisions. Typical workflow steps include specimen accessioning, slide preparation, initial probe staining, application of the additional single-probe ISH stain (88369), pathologist evaluation (interpretation and manual counting), and final reporting.
Typical site of service is the hospital pathology laboratory or independent reference laboratory. The service type is a laboratory-based anatomic pathology test involving molecular cytogenetic analysis of tumor tissue.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component |