Summary & Overview
CPT 87799: Quantitative Nucleic Acid Probe Infectious Agent Test
CPT code 87799 denotes a laboratory procedure that quantifies infection by an infectious agent using a nucleic acid probe technique when no more specific CPT code exists. This miscellaneous CPT code is used nationally by clinical and hospital laboratories to report quantitative probe-based nucleic acid testing for infectious agents not otherwise specified. It matters because it enables reporting and reimbursement for emerging or uncommon infectious-agent assays pending establishment of unique codes, and it affects laboratory billing consistency and claim adjudication across payers.
Key payers addressed include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise explanation of the code's clinical and billing role, typical sites of service, and common modifiers used with laboratory procedure reporting. The publication also summarizes what to expect in payer coverage approaches and claim processing for miscellaneous quantitative nucleic acid probe tests, identifies gaps where specific codes do not exist, and outlines areas where policy updates or new codes may be sought.
This analysis is written for a national audience and focuses on code definition, clinical context, and billing implications for laboratories and billing professionals. Data not provided in the input—such as payer-specific rates, associated taxonomies, and ICD-10 pairings—is noted as unavailable where applicable.
Billing Code Overview
CPT code 87799 describes a laboratory test in which the lab analyst quantifies infection with an infectious agent using a nucleic acid probe technique when no other specific code applies. The code is intended for quantification of an infectious agent not otherwise specified by an existing CPT code.
Service type: Quantitative nucleic acid probe infectious agent test
Typical site of service: Clinical laboratory or hospital laboratory
Data not available in the input.
Clinical & Coding Specifications
Clinical Context
A 42-year-old outpatient with persistent fever and rising inflammatory markers presents to an infectious disease clinic. The clinician suspects a viral or atypical bacterial infection not covered by standard panels and orders a laboratory quantification test using a nucleic acid probe technique to measure pathogen load. A blood specimen is collected in the clinic and sent to the hospital molecular diagnostics lab. The laboratory analyst performs an RNA/DNA probe–based quantitative assay to determine the amount of infectious agent nucleic acid present for clinical management, monitoring response to therapy, or guiding antiviral/antimicrobial decisions. Typical sites of service include hospital outpatient laboratories, independent reference laboratories, and some ambulatory surgery centers with molecular diagnostic capability. The service is billed when a quantification test is performed for an infectious agent that does not have a specific published CPT code, using nucleic acid probe methodology, and when results contribute to clinical decision-making such as treatment monitoring or infection control.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | Use when billing only the interpreting professional component of the laboratory test if separated from technical component billing. |
59 |