CPT 88367: ISH Single Probe Stain with Computer-Assisted Enumeration and Interpretation

CPT code 88367 covers in situ hybridization (ISH) single probe staining performed on slide(s) from a single patient specimen with computer-assisted enumeration and subsequent pathologist interpretation. This code captures a combined laboratory workflow where a trained lab analyst performs the initial staining and digital or automated counts, and a qualified provider issues the diagnostic interpretation. Nationally, ISH testing supports diagnosis, prognostication, and therapeutic decision-making in oncology and other specialty pathology areas, making accurate coding essential for clinical documentation and payment integrity.

Key payers addressed in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a practical overview of what 88367 represents, benchmarks and payer coverage patterns where available, coding and billing considerations tied to the service description, and clinical context for use in tumor tissue evaluation. Data not available in the input will be flagged explicitly. The publication focuses on policy and billing implications at a national level and provides reference points for laboratories, pathology groups, and compliance teams seeking concise guidance on the code's clinical and administrative role.

Billing Code Overview

CPT code 88367 describes an in situ hybridization (ISH) single probe assay workflow in which a laboratory analyst applies an initial ISH single probe stain to slide(s) prepared from a single patient specimen, commonly tumor tissue. The process uses computer-assisted technology to count or estimate probe signals, and a qualified provider—typically a pathologist—reviews the stained slides together with the computer enumeration to interpret the results and provide a pathologic diagnosis.

Service type: Laboratory pathology service involving ISH single probe staining with computer-assisted enumeration and pathologist interpretation
Typical site of service: Hospital pathology laboratory or independent diagnostic laboratory (clinical/laboratory setting)

Clinical Context

A 62-year-old woman with a history of luminal breast carcinoma presents after surveillance imaging and a core needle biopsy that demonstrates atypical cells. The surgical pathology specimen is submitted to the hospital pathology laboratory for confirmatory molecular testing. The lab analyst prepares formalin-fixed, paraffin-embedded tissue slides and applies an initial in situ hybridization single probe assay using computer-assisted image analysis to count probe signals. A board-certified pathologist reviews the stained slides, the computer enumeration output, and integrates morphologic findings to issue a diagnostic report confirming gene copy number alteration consistent with amplification or deletion that informs prognosis and targeted therapy selection. Typical site of service: hospital outpatient laboratory or independent reference laboratory with pathologist oversight.

Coding Specifications

Modifier	Description	When to Use
`26`	Professional component	Use when only the pathologist's interpretation/report (professional component) is billed separately from the laboratory technical processing.
`TC`	Technical component	Use when only the laboratory technical component (staining and image enumeration) is billed by the performing facility.

Taxonomy Code	Specialty	Notes
207RH0000X	Anatomic Pathology	Board-certified pathologists who interpret ISH and render the final report.
208000000X	Pathology	Clinical pathologists and laboratory medicine specialists involved in test validation and oversight.
261QM0800X	Molecular Genetic Pathology	Specialists who direct and interpret molecular and ISH testing for oncology.
363L00000X	Clinical Laboratory Director	Laboratory directors who oversee technical performance and compliance.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`C50.919`	Malignant neoplasm of unspecified site of unspecified female breast	Breast carcinoma commonly undergoes ISH testing for HER2 gene amplification to guide targeted therapy.
`C71.9`	Malignant neoplasm of brain, unspecified	Brain tumor specimens may require ISH for evaluation of gene amplifications or translocations relevant to prognosis or treatment.
`C34.90`	Malignant neoplasm of unspecified part of unspecified bronchus or lung	Lung carcinomas are frequently tested with ISH for ALK or ROS1 gene rearrangements or other copy number changes.
`C61`	Malignant neoplasm of prostate	Prostate tumors may have ISH testing for specific genomic alterations in selected cases.
`D49.3`	Neoplasm of uncertain behavior of skin	When molecular characterization is needed for atypical or uncertain cutaneous tumors, ISH can assist diagnosis.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`88367`	In situ hybridization (ISH), single probe, initial; lab analyst performs staining with computer-assisted enumeration and pathologist interprets	Primary procedure described; covers technical staining/enumeration plus professional interpretation workflow.
`88368`	In situ hybridization (ISH), single probe, subsequent probe; additional probe on same specimen	Performed when additional single-probe ISH assays are required on the same specimen for other targets.
`88377`	Morphometric analysis, such as image analysis of in situ hybridization, per specimen	May be reported for detailed image analysis or quantitation methods when billed separately depending on payer policy.
`88342`	Immunohistochemistry, per antibody; initial single antibody stain	Often performed alongside ISH to correlate protein expression with gene copy number for therapy selection.
`88305`	Level IV surgical pathology, gross and microscopic examination	Commonly billed for initial diagnostic histopathology evaluation of the tissue specimen preceding molecular ISH testing.

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Summary & Overview