Summary & Overview
CPT 0845T: Whole-Slide Image Digitization for Pathology
CPT code 0845T is an add‑on procedural code that captures clinical staff work to scan and digitize whole‑slide images from glass microscope slides to support immediate or deferred pathologic diagnosis. As digital pathology and telepathology applications expand, this code documents the additional labor associated with slide digitization separate from the primary staining and interpretation services. Nationally, accurate reporting of this code affects coding consistency, workflow documentation, and visibility into resource use for digital pathology.
Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise explanation of the code's clinical intent and service setting, guidance on typical reporting context, and pointers to related billing practices. The publication outlines benchmarking considerations for add‑on imaging services, common modifiers reported with imaging add‑on work, and the clinical implications for pathology workflows that adopt whole‑slide imaging. Data not available in the input is noted where applicable.
This summary is intended to inform coding staff, billing managers, and pathology leaders about the role of CPT code 0845T in documenting digitization work for immunofluorescent and other slide‑based diagnostic processes, and to clarify the national policy and billing context relevant to digital pathology adoption.
Billing Code Overview
CPT code 0845T describes clinical staff work to scan and digitize whole‑slide images from glass microscope slides for immediate or later pathologic diagnosis. This add‑on code is reported to reflect the labor involved in creating digital whole‑slide images that support microscopic review and diagnostic interpretation.
Service Type: Laboratory/pathology digitization and imaging support
Typical Site of Service: Anatomic pathology laboratory or hospital pathology department
Clinical & Coding Specifications
Clinical Context
A 62-year-old patient undergoes a renal biopsy for evaluation of rapidly progressive glomerulonephritis. Fresh biopsy tissue is processed in the pathology laboratory, and immunofluorescent antibody staining is performed to detect immune complex deposition. Clinical staff then scan the stained glass slides using a high-resolution whole–slide scanner to create digital images for immediate review by the pathologist and for inclusion in the permanent diagnostic record. The workflow includes slide accessioning, labeling, loading slides into the scanner, managing image capture settings, quality control of scanned images, and linking images to the patient’s pathology accession number in the laboratory information system. One unit of add-on code 0845T is reported for the clinical staff work to digitize the whole–slide image corresponding to one unit of code 88346 (initial immunofluorescent antibody stain). Typical site of service is the hospital-based or independent pathology laboratory associated with surgical pathology or renal pathology services. Common modifiers applicable to the claim include 22 (increased procedural services), 52 (reduced services), and 53 (discontinued procedure) to reflect atypical billing circumstances.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
22 | Increased procedural services | Use when the digitization required substantially greater work, e.g., complex multi-block slide sets or extensive manual image adjustments beyond typical scanning time. |
52 | Reduced services | Use when scanning was partially performed or limited relative to the usual procedure, such as fewer required fields captured. |
53 | Discontinued procedure | Use when scanning was started but terminated for clinical or technical reasons prior to completion. |
59 | Distinct procedural service | Use when multiple distinct scanning events for separate specimens on the same date need separation (use with caution and appropriate documentation). |
76 | Repeat procedure by same provider | Use when the same facility repeats a whole–slide digitization on the same day due to technical failure. |
77 | Repeat procedure by another provider | Use when a second facility repeats digitization after transfer for quality assurance or second opinion. |
90 | Reference (outside) laboratory | Use when scanning service is performed by an outside laboratory and billed by the referring lab. |
91 | Repeat clinical diagnostic laboratory test | Use when repeat digitization is performed for verification within a short interval per laboratory protocol. |
RT | Right side | Rarely applicable; use when laterality-specific labeling is required and reported by policy for associated specimen handling. |
LT | Left side | Rarely applicable; use when laterality-specific labeling is required and reported by policy for associated specimen handling. |
| Taxonomy Code | Specialty | Notes |
|---|---|---|
Data not available in the input. | ||
207RH0000X | Pathology | Board-certified pathologists interpret immunofluorescence images and oversee scanning workflows. |
207K00000X | Clinical Laboratory | Laboratory directors and clinical lab staff manage slide processing and digital imaging operations. |
208100000X | Pathologist Assistant | Pathologist assistants or histotechnologists perform slide preparation and scanning under supervision. |
163W00000X | Hospitalist (Laboratory Medicine) | Laboratory medicine specialists coordinate diagnostic testing and reporting in hospital settings. |
Related Diagnoses
| ICD-10 Code | Description | Clinical Relevance |
|---|---|---|
N00.9 | Acute nephritic syndrome, unspecified | Immunofluorescence and slide digitization are commonly used to evaluate immune complex deposition in nephritic syndromes. |
N01.9 | Rapidly progressive nephritic syndrome, unspecified | Immunofluorescent studies and whole–slide imaging support diagnosis and quantification of glomerular immune deposits. |
N03.9 | Chronic nephritic syndrome, unspecified | Digital immunofluorescence images assist in longitudinal review and consultation for chronic glomerular disease. |
N04.9 | Nephrotic syndrome with unspecified morphologic changes | Immunofluorescence helps identify podocyte immune patterns; scanned images are used for reporting and remote review. |
N05.9 | Unspecified glomerulonephritis | General glomerular disease evaluation frequently employs immunofluorescent stains and whole–slide digitization. |
R79.9 | Abnormal clinical chemistry of blood, unspecified | Abnormal serologies prompting renal biopsy can correlate with immunofluorescence findings captured by digital slides. |
Z01.818 | Encounter for other preprocedural examination | Pre-biopsy workup and documentation often accompany procedures that lead to immunofluorescent staining and digitization. |
Related CPT Codes
| CPT Code | Description | Relationship to This Procedure |
|---|---|---|
88346 | Initial immunofluorescent antibody stain, single antibody stain | 0845T is reported one unit per unit of 88346 to document clinical staff work scanning the corresponding immunofluorescent stained slide. |
88342 | Immunohistochemistry or immunoperoxidase, per specimen; initial single antibody stain | May be performed alongside immunofluorescence staining; separate scanning for immunohistochemistry slides may be billed similarly if digital imaging services are provided. |
88311 | Decalcification procedure for bone, skull, or other specimens | Pre-analytic specimen processing code that can precede staining and scanning when tissue requires decalcification. |
88305 | Level IV surgical pathology, gross and microscopic examination | Represents primary surgical pathology interpretation; scanned immunofluorescence images support the microscopic correlation documented in 88305. |
0009M | Digital pathology whole slide imaging, per slide (example proprietary/industry code) | Proprietary or G-code level billing for digital pathology scanning may be used in some contexts; 0845T specifically captures clinical staff work for digitizing slides tied to immunofluorescence staining. |