CPT 0515U: Procise IFX™ Infliximab Quantitative Immunoassay

CPT code 0515U designates a Proprietary Laboratory Analyses (PLA) test for Procise IFX™ (ProciseDx Inc.), an immunoassay that quantitatively measures infliximab (IFX) levels in venous serum and reports results in µg/mL. This single-source PLA code matters nationally as therapeutic drug monitoring for biologic agents like infliximab increasingly informs dosing adjustments, treatment decisions, and value-based care models.

Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. The coverage landscape for proprietary assays varies by payer policy, medical necessity criteria, and lab-provider contracting; stakeholders should reference each payer’s laboratory and specialty drug monitoring policies for specifics.

Readers will learn the clinical context for 0515U—therapeutic drug monitoring of infliximab—along with typical sites of service and how a PLA code differs from generic laboratory CPT codes. The publication provides benchmarks and payer coverage considerations, highlights policy and coding implications for single-manufacturer laboratory tests, and summarizes operational points relevant to laboratory billing and documentation. Data not available in the input will be noted where applicable.

Billing Code Overview

CPT code 0515U is a Proprietary Laboratory Analyses (PLA) code that applies only to a single, manufacturer- or lab-specific test. Report 0515U only for Procise IFX™ from ProciseDx Inc. The test uses an immunoassay to quantitatively measure infliximab (IFX) levels in venous serum and reports results in micrograms per milliliter (µg/mL).

Service type: Quantitative therapeutic drug monitoring assay for infliximab levels
Typical site of service: Clinical laboratory or outpatient phlebotomy/serology service

Clinical Context

A 38-year-old patient with moderate-to-severe Crohn disease receiving maintenance infliximab therapy presents for routine therapeutic drug monitoring due to loss of response and intermittent abdominal pain. The gastroenterology clinic orders Procise IFX™ (0515U) to quantitatively measure serum infliximab levels prior to the next scheduled infusion. Blood is drawn from a venous specimen collection in the outpatient lab or infusion center; the specimen is sent to the performing laboratory or the manufacturer-designated testing site. The laboratory performs an immunoassay and reports the infliximab concentration in micrograms per milliliter (µg/mL). Results inform interpretation of drug exposure, potential anti-drug antibody assessment (if clinically ordered separately), and next steps in the therapeutic plan such as dose adjustment, interval change, or consideration of alternate biologic therapy.

Coding Specifications

Modifier	Description	When to Use
`00`	Default - no modifier	Applied when no other modifier is appropriate
`26`	Professional component

Taxonomy Code	Specialty	Notes
207RG0100X	Gastroenterology	Gastroenterologists commonly order infliximab level testing to manage IBD therapy
207RH0000X	Internal Medicine	Internists or hospitalists managing biologic therapy may order therapeutic drug monitoring
207QH0002X	Pediatric Gastroenterology	Pediatric gastroenterologists order drug levels for children on infliximab
261QM0800X	Laboratory Medicine	Pathologists and clinical laboratory directors oversee testing and result validation
363L00000X	Infusion Center	Infusion nurses and centers coordinate specimen collection prior to infusions

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`K50.00`	Crohn disease of small intestine without complications	Crohn disease patients on infliximab commonly require drug level monitoring
`K50.90`	Crohn disease, unspecified, without complications	General Crohn disease diagnosis associated with infliximab therapy
`K51.90`	Ulcerative colitis, unspecified, without complications	Ulcerative colitis patients treated with infliximab may require therapeutic monitoring
`M06.9`	Rheumatoid arthritis, unspecified	Some rheumatologic conditions treated with infliximab where serum drug levels are clinically relevant
`M45.9`	Ankylosing spondylitis, unspecified	Spondyloarthropathies treated with infliximab that may require TDM (therapeutic drug monitoring)

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`36415`	Collection of venous blood by venipuncture	Venous specimen collection required prior to performing the `0515U` assay
`80053`	Comprehensive metabolic panel	Common concurrent laboratory testing ordered during infusion visits to assess baseline chemistry
`86644`	Infliximab (therapeutic) antibody, qualitative or semi-quantitative	Complementary testing when anti-drug antibodies are suspected alongside infliximab level measurement
`84702`	Therapeutic drug assay, other (e.g., biologic drug concentration)	General category code sometimes used for non-proprietary assays measuring biologic drugs
`99000`	Handling and/or conveyance of specimen for transfer from physician office to outside lab	Billing element used in some settings when specimens are transported to external performing laboratories

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Summary & Overview