CPT 87798: Amplified Nucleic Acid Probe Test for Unspecified Infectious Agent
CPT code 87798 covers an amplified nucleic acid probe assay used when a laboratory performs testing for an infectious agent not specified by another code. This miscellaneous molecular diagnostic code matters nationally because it enables reporting of amplified probe techniques when no pathogen-specific CPT code exists, supporting clinical decision-making and lab reimbursement for uncommon or novel targets.
Key payers discussed include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise explanation of the code’s clinical scope and typical laboratory setting, an overview of payer coverage patterns and common modifiers used with molecular diagnostics, and context for how 87798 fits within laboratory billing workflows. The publication highlights benchmarking considerations for labs that report nonspecific amplified probe testing, policy and coverage themes that affect national reimbursement approaches, and clinical implications for infectious disease diagnostics. Data not available in the input for specific payer fee schedules, utilization rates, and ICD-10 pairings are noted where applicable.
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Billing Code Overview
CPT code 87798 describes a laboratory service in which a lab analyst performs an amplified nucleic acid probe test for an infectious agent that is not otherwise specified by another code. The service type is a specialized infectious disease molecular diagnostic test using an amplified probe technique. The typical site of service is a clinical laboratory or other laboratory setting where molecular diagnostic assays are performed, including hospital laboratories and independent diagnostic labs.
Clinical & Coding Specifications
Clinical Context
A patient presents to an outpatient infectious disease clinic with persistent fever, malaise, and no clear source after broad empiric evaluation. The clinician collects a nasopharyngeal swab and orders a targeted nucleic acid amplification test using an amplified probe technique for an infectious agent not represented by a specific CPT code. The specimen is transported to a clinical laboratory. A molecular technologist or lab analyst performs the amplified nucleic acid probe assay in a molecular diagnostics laboratory, documents analytic run data, interprets signal detection, and reports a qualitative result to the ordering clinician. Results inform infection control decisions and targeted therapy. Typical site of service is a hospital-based or independent clinical molecular laboratory supporting outpatient clinics and inpatient services; specimen collection occurs in clinic, emergency department, or hospital floor settings.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | Use when billing only the physician interpretation of the laboratory result separate from the technical lab work (rare for this code). |
59 | Distinct procedural service | Use when this amplified probe test is distinct and unrelated to another laboratory molecular procedure performed the same day. |
90 | Reference (outside) laboratory | Use when the performing laboratory is an outside reference lab billing for the test. |
91 | Repeat clinical diagnostic laboratory test | Use when a repeat amplified probe test is performed on the same patient to confirm a prior result. |
92 | Alternative laboratory platform test | Use when the test is performed using a new or experimental platform that lacks an established code and payer requires reporting of the method. |
QW | CLIA-waived test (reagent/device) | Use if the specific amplified probe assay is a CLIA-waived method (uncommon for amplified probe techniques). |
TC | Technical component | Use when billing only the laboratory technical component (instruments, reagents, technologist time) separate from any interpreting professional service. |
22 | Increased procedural services | Use when work, time, or complexity substantially exceeds typical for the test (documented and rare for standardized assays). |
52 | Reduced services | Use when the service provided is partially reduced or discontinued (for example, interrupted run yielding partial analysis). |
76 | Repeat procedure by same physician | Use when the same lab performs a repeated amplified probe test during the same encounter. |
78 | Unplanned return to the lab for related procedure | Use if an unexpected repeat specimen or re-run is required due to instrument failure. |
90 | Reference (outside) laboratory | Use when results are produced by an outside reference laboratory and billed accordingly. |
91 | Repeat clinical diagnostic laboratory test | Use for repeat testing to confirm or follow-up an earlier result. |
59 | Distinct procedural service | Use to indicate a distinct test when multiple assays are performed on the same specimen. |
| Taxonomy Code | Specialty | Notes |
|---|---|---|
| 207RG0100X | Infectious Disease | Physicians ordering complex molecular diagnostics and interpreting results. |
| 207L00000X | Pathology | Pathologists overseeing molecular laboratories and result validation. |
| 364S00000X | Laboratory Director | Clinical laboratory directors who supervise molecular test performance and reporting. |
| 334J00000X | Clinical Molecular Biology | Laboratory scientists and molecular technologists performing amplified probe assays. |
| 261QM0800X | Hospital/Clinic Laboratory | Institutional laboratory services performing the technical component. |
Related Diagnoses
| ICD-10 Code | Description | Clinical Relevance |
|---|---|---|
R50.9 | Fever, unspecified | Common presenting symptom prompting infectious agent testing with an amplified nucleic acid probe. |
R68.84 | Chills (without fever) | Associated systemic symptoms that may prompt molecular infectious testing. |
A41.9 | Sepsis, unspecified organism | Severe presentations where broad molecular testing for uncommon pathogens may be ordered. |
J06.9 | Acute upper respiratory infection, unspecified | Respiratory symptoms often trigger amplified probe testing when specific agents are not yet identified. |
N76.0 | Acute vaginitis | Genital symptoms where amplified nucleic acid testing for infectious agents may be performed when no specific CPT exists. |
O99.8 | Other specified diseases and conditions complicating pregnancy, not elsewhere classified | In pregnancy, molecular testing for atypical pathogens without specific CPT codes may be required. |
B99 | Other and unspecified infectious diseases | Used when infection is suspected but the exact infectious agent is not yet identified and requires broad molecular testing. |
Related CPT Codes
| CPT Code | Description | Relationship to This Procedure |
|---|---|---|
87471 | Infectious agent detection by nucleic acid (e.g., amplified probe technique), Influenza; direct probe technique (qualitative), each type | Performed when a specific influenza amplified probe assay exists; 87798 is used when no specific code for the agent exists. |
87624 | Infectious agent detection by nucleic acid (e.g., amplified probe technique), SARS-CoV-2, amplified probe technique, each specimen | A commonly ordered specific amplified probe assay; billed instead of 87798 when SARS-CoV-2 is the target and a specific code applies. |
87631 | Infectious agent detection by nucleic acid (e.g., amplified probe technique), group A streptococcus (e.g., throat), amplified probe technique | An example of a specific agent code for which 87798 would not be used if the agent matches a specific CPT. |
87491 | Infectious agent detection by nucleic acid (e.g., amplified probe technique), Group B Streptococcus | Relevant when testing for common obstetric pathogens; 87798 applies when agent lacks a specific code. |
88305 | Surgical pathology, gross and microscopic examination | May be performed in parallel for tissue specimens when molecular testing is adjunctive to pathology evaluation. |