Summary & Overview
CPT 0849T: Digital Whole–Slide Image Scanning for In Situ Hybridization
CPT code 0849T is an add–on code for clinical staff work to scan and digitize whole–slide images from glass microscope slides to support immediate or later pathologic diagnosis. It is reported one unit per unit of the associated single–probe in situ hybridization stain procedure +88364. The code matters nationally as pathology and diagnostic labs increasingly adopt digital workflows for slide review, telepathology, quality assurance, and archival purposes; accurate coding ensures capture of the digitization labor separate from the stain procedure itself.
Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will learn how 0849T is defined and used in clinical lab settings, the typical service setting where it applies, common modifiers and reporting practices (where available), and which payers are relevant for coverage considerations. The report also outlines the clinical context—digital whole–slide imaging paired with in situ hybridization—and highlights where data was not provided.
This concise overview addresses coding intent, service delivery context, and payer scope at a national level to inform billing, revenue cycle, and pathology operations teams.
Billing Code Overview
CPT code 0849T describes clinical staff work to scan and digitize whole–slide images from glass microscope slides for immediate or later pathologic diagnosis. The code is an add–on digitization service reported per unit of the associated in situ hybridization stain procedure described by code +88364.
Service type: Pathology / Diagnostic Laboratory — Digital Slide Scanning and Image Digitization
Typical site of service: Hospital-based pathology labs, independent pathology laboratories, and outpatient diagnostic laboratories
Clinical & Coding Specifications
Clinical Context
A 62-year-old patient undergoes a diagnostic workup for a suspicious prostate biopsy with focal atypia on hematoxylin and eosin (H&E) slides. The anatomic pathology laboratory performs an in situ hybridization (ISH) single-probe stain to evaluate a specific molecular target on one tissue slide. Clinical staff scan the glass slide(s) to create whole-slide digital images for immediate review by the pathologist and for archiving. The workflow includes accessioning the specimen, preparing and staining the slide, performing quality control on the ISH stain, scanning the slide using a validated scanner, verifying image fidelity, and linking the digitized image to the patient’s pathology report and laboratory information system. The digitized whole-slide image supports primary or ancillary diagnosis, enables remote pathologist review, and facilitates image-based consultation and tumor board review.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
22 | Increased procedural services | When scanning required substantially greater technical effort or time due to unusually complex slide preparation or scanning (documented) |
52 | Reduced services | When the scanning service is partially performed or reduced in scope compared with standard practice
53 | Discontinued procedure | When the scanning process was started but terminated due to unforeseen events (e.g., scanner failure) prior to completion
QW | CLIA-waived testing (not typically applicable) | Generally not used for pathology whole-slide scanning; avoid unless facility CLIA status requires
TC | Technical component | Use if reporting only the technical component of services when applicable (rare for this add-on clinical staff code)
26 | Professional component | Use if reporting the pathologist’s professional interpretation separate from the scanning staff activity
90 | Reference (outside) laboratory | When scanning or ancillary testing performed by an outside reference laboratory
59 | Distinct procedural service | When scanning is performed on a separate and distinct specimen/site the same day as other procedures
XE | Separate encounter | When scanning is performed in a separate encounter from other services (use per payer rules)
Q6 | Service furnished under a departmental outpatient clinic | When the scanning is performed within a hospital-based outpatient laboratory (per payer requirements)
| Taxonomy Code | Specialty | Notes |
|---|---|---|
207P00000X | Anatomic Pathology | Pathologists direct staining and interpretation workflows and order digital scans |
207L00000X | Pathology - Laboratory | Laboratory directors and senior technologists oversee scanning validation and QC
390200000X | Histology Technician | Histology technicians prepare slides and perform staining prior to scanning
338N00000X | Diagnostic Molecular Pathology | Molecular pathologists order and use ISH images for molecular diagnostic interpretation
Related Diagnoses
| ICD-10 Code | Description | Clinical Relevance |
|---|---|---|
C61 | Malignant neoplasm of prostate | Prostate biopsy specimens frequently undergo ISH or ancillary studies; slides from these procedures are scanned for diagnosis and consultation |
D07.5 | Carcinoma in situ of prostate | High-risk intraepithelial lesions may prompt ancillary ISH testing and slide digitization
N40.0 | Benign prostatic hyperplasia with lower urinary tract symptoms | Benign specimens sometimes require ancillary stains for differential diagnosis and are scanned for review
C50.919 | Malignant neoplasm of unspecified site of right female breast | Breast core biopsies commonly require ISH (e.g., HER2) and whole-slide scanning for interpretation
C18.9 | Malignant neoplasm of colon, unspecified | Colorectal cancer specimens may undergo molecular ISH testing; resulting slides are scanned for pathology workflows
Related CPT Codes
| CPT Code | Description | Relationship to This Procedure |
|---|---|---|
+88364 | In situ hybridization (e.g., FISH), single probe, each additional single probe | Primary ancillary staining procedure for which +0849T is reported per unit; scanning digitizes slides produced by this ISH procedure |
88342 | Immunohistochemistry or immunocytochemistry, per specimen; initial single antibody stain | Often performed alongside ISH on adjacent sections; scanned when digital review is needed
88305 | Level IV surgical pathology, gross and microscopic examination | Primary pathology evaluation of biopsy or resection specimens that generate slides subsequently stained and scanned
88331 | Cytopathology, immediate cytohistologic evaluation for adequacy | Rapid onsite evaluation may precede subsequent ISH stains and scanning in some workflows
87471 | Infectious agent detection by nucleic acid (e.g., HPV) | Molecular tests that may be ordered in the same diagnostic episode; resulting slides or images may be correlated with ISH findings