Summary & Overview
CPT 88749: Unlisted In Vivo Laboratory Service
CPT code 88749 designates unlisted in vivo laboratory services and is applied when a specific CPT code is not available for the laboratory procedure performed. Nationally, this code matters because it provides a billing pathway for novel, rare, or evolving in vivo tests that lack discrete coding, ensuring such services can be reported and considered for coverage or review. The analysis covers major national payers, including Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare.
Readers will learn what 88749 represents clinically and operationally, how common payers address unlisted in vivo laboratory services, and which documentation elements and billing practices are typically important when reporting an unlisted in vivo test. The publication summarizes benchmarks and common billing patterns where available, highlights relevant policy considerations for national payers, and explains the clinical context in which an unlisted in vivo laboratory service is used. Data not available in the input is noted where applicable.
Billing Code Overview
CPT code 88749 is used to report unlisted in vivo laboratory services when no specific CPT code exists for the procedure performed. This code captures novel, atypical, or otherwise unclassified in vivo laboratory tests that are performed and reported without a designated code.
Service type: In vivo laboratory testing (unlisted service)
Typical site of service: Clinical laboratory or hospital-based laboratory performing in vivo testing, depending on where the unlisted in vivo procedure is performed.
Clinical & Coding Specifications
Clinical Context
A clinical laboratory receives a request to perform an in vivo diagnostic test that does not have an established CPT code. The patient is a 56-year-old oncology patient undergoing evaluation for suspected treatment-related marrow toxicity. The ordering clinician requests a specialized in vivo assay to measure biologic response markers following administration of a study agent. The workflow: the clinician documents medical necessity and specific test methodology in the order; the specimen or patient encounter is processed in a hospital clinical laboratory or an independent diagnostic testing facility; the laboratory performs the custom in vivo assay and generates a formal report. Billing uses 88749 as an unlisted in vivo laboratory service. Documentation includes the report, methodology, time/date, physician or laboratory professional who performed or interpreted the assay, and any written justification for use of an unlisted code for payer review. Insurance adjudication may require submission of procedural details, test validation data, and a comparable code or cost report for pricing determination.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
22 | Increased Procedural Services | Use when the laboratory documents significantly increased work or complexity for the unlisted in vivo assay requiring additional reimbursement justification. |