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.