CPT 0511U: PARIS 3D Tumor Drug Response Profiling

CPT code 0511U designates a proprietary laboratory test — PARIS from Tempus AI Inc. — that cultures tumor cells in a 3D microenvironment to assess responses to 36 or more drugs and generate drug-specific effectiveness predictions. As a PLA code, 0511U is unique to a single manufacturer’s lab test and is used to identify the PARIS assay in claims and administrative data. This code matters nationally as precision oncology diagnostics and tumor functional profiling increasingly inform therapeutic selection and payer coverage determinations.

Key payers in the coverage landscape include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare and Medicare. Readers will find a concise overview of the clinical method and intended use of the PARIS test, the payer mix relevant to national coverage discussions, and the types of analyses typically reported for PLA codes (coverage benchmarks, reimbursement context, and policy considerations). The publication highlights how 0511U is captured in billing systems, where the test is usually performed, and what stakeholders commonly examine when evaluating novel laboratory assays for clinical utility and coverage.

Billing Code Overview

CPT code 0511U is a Proprietary Laboratory Analyses (PLA) code that applies exclusively to a single, manufacturer-specific laboratory test. Report 0511U only for PARIS from Tempus AI Inc. The assay cultures tumor cells in a 3D microenvironment and evaluates their responses to 36 or more anticancer drugs, producing drug-specific effectiveness predictions.

Service type: Laboratory diagnostic assay using ex vivo 3D tumor cell culture and pharmacologic response profiling.
Typical site of service: Commercial clinical laboratories or specialized molecular diagnostics laboratories; test is performed on patient tumor specimens sent to the performing laboratory.

Clinical Context

A typical patient is an adult with a histologically confirmed solid tumor who has progressed on or is intolerant of standard systemic therapies and for whom personalized functional drug-sensitivity data are requested to guide later-line systemic treatment decisions. A treating oncologist obtains a viable tumor specimen (core needle biopsy or surgical resection) which is shipped to the performing laboratory. The laboratory (Tempus AI Inc. for PARIS) cultures patient tumor cells in a 3D microenvironment, exposes them to a panel of 36 or more anticancer agents, and reports predicted sensitivity/resistance for each drug. Results return to the ordering oncologist and are reviewed in a clinical visit or tumor board to inform selection of off-label agents, clinical trial matching, or supportive decision-making. Typical site of service is an outpatient pathology/molecular diagnostics laboratory with specimen collection performed in an outpatient clinic, ambulatory surgery center, or hospital outpatient department. Billing uses PLA code 0511U uniquely for the PARIS test from Tempus AI Inc.

Coding Specifications

Modifier	Description	When to Use
`26`	Professional component	When billing only the professional interpretation component if separated by the performing laboratory and billing provider

Taxonomy Code	Specialty	Notes
208000000X	Hematology/Oncology	Ordering and interpreting oncologists who request genomic/functional tumor profiling
207RC0000X	Anatomic and Clinical Pathology	Pathology laboratories responsible for specimen handling and processing
208600000X	Medical Oncology	Medical oncologists who use results for systemic therapy selection
207LP2900X	Molecular Pathology	Specialists overseeing molecular and functional diagnostic testing
261QM0800X	Diagnostic Laboratory	Laboratories performing complex laboratory analyses and reporting

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`C80.1`	Malignant neoplasm, unspecified, with metastasis	Advanced metastatic cancer commonly evaluated with functional assays to guide later-line systemic therapy selection
`C78.7`	Secondary malignant neoplasm of liver and intrahepatic bile duct	Common metastatic site for which tumor profiling may influence systemic therapy choices
`C78.2`	Secondary malignant neoplasm of lung	Metastatic disease to lung where biopsy specimens are often submitted for functional testing
`C50.9`	Malignant neoplasm of breast, unspecified	Breast cancer patients with progression after standard therapy may undergo ex vivo drug sensitivity testing
`C34.90`	Malignant neoplasm of unspecified part of bronchus or lung	Lung cancer frequently evaluated with advanced functional and molecular assays to guide therapy

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`88305`	Level IV surgical pathology, gross and microscopic examination	Performed when initial tumor biopsy is reviewed to confirm diagnosis prior to sending specimen for functional testing
`88182`	Cytopathology, cell block preparation	Used if a cell block is prepared from fine-needle aspirate or effusion to provide material for PARIS testing
`88342`	Immunohistochemistry, per single stain/antibody	Performed to characterize tumor subtype which may be required prior to or concurrent with functional assay interpretation
`88173`	Cytopathology, immunocytochemistry	Used when immunocytochemical stains are applied to specimen prior to functional culture
`G0452`	Oncology (cancer) care planning and coordination services (complex)	Used by clinicians when integrating specialized laboratory results into complex care planning or multidisciplinary tumor board review

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Summary & Overview