Summary & Overview
CPT 0314U: DecisionDx DiffDx Melanoma RT–PCR Gene Expression Test
CPT code 0314U designates DecisionDx® DiffDx™ Melanoma, a proprietary laboratory analysis that evaluates FFPE skin lesion specimens using RT–PCR gene expression profiling of 35 genes to classify lesions as benign, intermediate, or malignant. As a PLA code tied to a single manufacturer's test, it communicates a specific test identity and methodology for billing and coverage decisions. Nationally, PLA codes like 0314U matter because they enable unique identification of advanced molecular diagnostics that influence clinical management of suspected melanoma and inform payer coverage and laboratory reimbursement policies.
Key payers in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of the test's clinical purpose and technical approach, payer coverage landscape, common billing modifiers associated with the service, and the clinical context for use in evaluating suspicious cutaneous lesions. The publication also summarizes benchmarks and policy updates relevant to proprietary molecular assays, and highlights coding considerations when reporting a PLA test performed on FFPE biopsy material.
This resource is intended for billing specialists, laboratory managers, clinicians ordering molecular diagnostics for melanoma evaluation, and policy analysts seeking a national perspective on coding and coverage for a manufacturer-specific gene expression assay.
Billing Code Overview
CPT code 0314U is a Proprietary Laboratory Analyses (PLA) code for DecisionDx® DiffDx™ Melanoma from Castle Biosciences Inc. The test is performed on formalin–fixed paraffin–embedded (FFPE) tissue from a skin lesion suspicious for cutaneous melanoma and uses reverse–transcription polymerase chain reaction (RT–PCR) gene expression profiling. The assay analyzes the activity of 35 genes (32 content and three housekeeping) and applies an algorithmic analysis to categorize the lesion as benign, intermediate, or malignant.
Service type: Proprietary molecular diagnostic laboratory test (PLA) using RT–PCR gene expression profiling.
Typical site of service: Clinical laboratory or pathology/laboratory facility processing FFPE skin biopsy specimens.
Clinical & Coding Specifications
Clinical Context
A 58-year-old patient presents to dermatology with an evolving pigmented skin lesion on the upper back that is clinically suspicious for cutaneous melanoma. The dermatologist performs a skin biopsy (shave or punch) and submits the formalin–fixed paraffin–embedded (FFPE) tissue block to the pathology laboratory. After histopathologic review, the pathologist documents uncertainty about malignant potential (for example, an atypical Spitz tumor or an ambiguous melanocytic proliferation). The treating clinician orders the 0314U DecisionDx® DiffDx™ Melanoma gene expression profile to assist in risk stratification. The laboratory performs reverse–transcription polymerase chain reaction (RT–PCR) on RNA extracted from the FFPE sample, measures expression of 35 genes (32 content genes and three housekeeping genes), and applies the algorithm to classify the lesion as benign, intermediate, or malignant. Results are reported to the ordering clinician, who integrates molecular classification with histology to guide surveillance frequency, need for wider excision, sentinel lymph node biopsy consideration, or referral to surgical oncology or dermatopathology.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
00 | No modifier used / default | Use when no special modifier applies to the billed 0314U PLA test. |
26 | Professional component | Use when billing only the physician/pathologist professional interpretation component of the test if separated from technical service. |
TC | Technical component | Use when billing only the laboratory technical component (processing, assay) of the test if separated from professional interpretation. |
52 | Reduced services | Use when the laboratory performs a limited or partial version of the test resulting in reduced service. |
53 | Discontinued procedure | Use if testing was started but discontinued for clinical or specimen-related reasons. |
55 | Postoperative management only | Use when only postoperative follow-up services are billed by a provider (rare for lab tests; included if applicable to associated services). |
62 | Two surgeons | Use on related surgical claims when two surgeons shared responsibility; not applied to the lab code itself but relevant in the overall episode of care. |
78 | Unplanned return to OR | Use on surgical claims if a related unplanned return to the operating room occurs; relevant in the episode of care documentation. |
80 | Assistant surgeon | Use on surgical claims when an assistant surgeon participated; may affect global surgical billing related to biopsy/excision. |
82 | Assistant (when qualified resident not available) | Use when an assistant is required and no qualified resident is available; applies to surgical component of care. |
AS | Physician assistant, nurse practitioner, or clinical nurse specialist services | Use on professional services claims where advanced practice clinicians bill for related evaluation or specimen collection. |
QK | Medical direction of two, three, or four assistants | Use when applicable to the surgical episode; included for completeness in coordinated care scenarios. |
QX | CRNA service with medical direction | Use when relevant to anesthesia services associated with excision biopsies; not applied to the lab test itself. |
QY | Medical direction of one certified registered nurse anesthetist | Same context as QX for anesthesia billing. |
| Taxonomy Code | Specialty | Notes |
|---|---|---|
| 207N00000X | Dermatology | Dermatologists commonly obtain biopsies and order molecular testing for ambiguous melanocytic lesions. |
| 207P00000X | Pathology | Anatomic pathologists/dermatopathologists interpret histology and may order or interpret molecular test results. |
| 207L00000X | Medical Genetics | Molecular diagnostics laboratories and medical geneticists may be involved in test interpretation and result integration. |
| 2085P0200X | Surgical Oncology | Surgical oncologists may use results to decide on wider excision or sentinel lymph node biopsy. |
| 363L00000X | Clinical Laboratory | Clinical laboratory personnel perform the RT–PCR assay and report the technical component of the PLA test. |
Related Diagnoses
| ICD-10 Code | Description | Clinical Relevance |
|---|---|---|
D03.9 | Melanoma in situ, unspecified | Used when atypical lesion is initially diagnosed as in situ melanoma; molecular test can aid classification. |
C43.9 | Malignant melanoma of skin, unspecified | Applied when invasive melanoma is diagnosed or suspected; 0314U assists in differentiating malignant from benign. |
D22.9 | Melanocytic nevi, unspecified | Common benign differential diagnosis for lesions evaluated with molecular profiling when histology is ambiguous. |
D23.9 | Other benign neoplasm of skin, unspecified | Used for nonmelanocytic benign lesions in differential diagnosis; helps contextualize test results. |
R21 | Rash and other nonspecific skin eruption | When initial presentation is nonspecific and biopsy is performed; less specific but occasionally used. |
Related CPT Codes
| CPT Code | Description | Relationship to This Procedure |
|---|---|---|
11102 | Tangential biopsy of skin (eg, shave, scoop), single lesion; for lesion(s) suspicious for melanoma this may be the initial diagnostic specimen submitted for the 0314U test. | Performed before 0314U; provides the FFPE tissue required for molecular analysis. |
11104 | Tangential biopsy of skin, each additional lesion (List separately in addition to code for primary procedure). | Billed when multiple suspicious lesions are biopsied during the same encounter prior to sending tissue for molecular testing. |
11100 | Biopsy of skin, single lesion, punch, or incisional technique (separate procedure code depending on technique). | Alternative initial biopsy technique providing tissue for the 0314U assay. |
88305 | Level IV surgical pathology, gross and microscopic examination (e.g., skin excision or biopsy). | Pathology review code commonly billed for histologic examination of the biopsy specimen before or concurrent with ordering 0314U. |
88342 | Immunohistochemistry, per specimen; each additional stain (List separately in addition to code for primary procedure). | Ancillary immunohistochemical stains often used alongside molecular testing to characterize ambiguous melanocytic proliferations. |
0100U | Example PLA code (placeholder) | Data not available in the input. |