CPT 87118 AFB Identification Reimbursement

CPT code 87118 covers definitive identification testing performed on presumptively identified acid–fast bacilli (AFB) isolates, often to the species level. This code captures specialized laboratory procedures that follow initial AFB detection and are critical for guiding infectious disease management and public health surveillance. Nationally, accurate AFB species identification affects antimicrobial selection and reporting for mycobacterial infections, making this code relevant for clinical microbiology labs and hospital systems.

Key payers in the analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find an overview of clinical context and the laboratory setting where this service occurs, a summary of common modifiers and billing considerations, and a review of payer coverage patterns and benchmarks where available. The publication also outlines policy updates affecting laboratory billing and practical notes on documentation that support medical necessity for definitive AFB identification.

The report is intended for billing managers, laboratory directors, and policy analysts seeking concise guidance on how CPT code 87118 is used in practice, how major payers approach coverage, and what documentation and coding considerations typically accompany definitive AFB identification services.

Billing Code Overview

CPT code 87118 describes laboratory work in which a lab analyst performs additional testing on a presumptively identified acid–fast bacillus (AFB) isolate to achieve definitive identification, typically to the level of species. This service represents targeted microbiology identification procedures that follow initial presumptive AFB detection.

Service type: Definitive microbial identification testing for AFB isolates
Typical site of service: Clinical laboratory or hospital laboratory setting where microbiology cultures and specialty identification assays are performed

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Clinical Context

A patient presents to an infectious disease clinic or hospital inpatient unit with symptoms suggestive of pulmonary mycobacterial infection (for example, chronic cough, weight loss, night sweats) or a previously identified acid–fast bacillus (AFB) isolate from a respiratory specimen. The clinical laboratory performs initial AFB smear and culture. When an isolate is presumptively identified as an AFB, a laboratory analyst performs definitive identification to species level using additional tests such as nucleic acid probes, biochemical testing, MALDI-TOF, or molecular sequencing. Typical workflow: specimen collection (sputum, bronchoalveolar lavage, tissue) → AFB smear and culture → presumptive identification → reporting of presumptive result to ordering clinician → reflex or ordered confirmatory testing coded with 87118 → final identification reported to clinical team for targeted therapy decisions. Typical site of service: hospital microbiology laboratory, reference laboratory, or outpatient hospital-associated lab. Typical patient scenario: an adult with chronic respiratory symptoms and a positive AFB culture requiring species-level identification to distinguish Mycobacterium tuberculosis from nontuberculous mycobacteria for infection control and treatment planning.

Coding Specifications

Modifier	Description	When to Use
`26`	Professional component	When only the professional interpretation component is billed separately by the laboratory director or pathologist for the test result.

Taxonomy Code	Specialty	Notes
`207K00000X`	Pathology	Laboratory directors and pathologists overseeing microbiology testing and result interpretation.
`207L00000X`	Clinical Laboratory	Clinical laboratory scientists and microbiologists performing testing and analysis.
`207LP2900X`	Medical Microbiology	Specialists in clinical microbiology who perform advanced organism identification and molecular testing.
`207RG0400X`	Infectious Disease	Infectious disease physicians ordering confirmatory species identification to guide therapy.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`A15.0`	Tuberculosis of lung	Species-level identification distinguishes Mycobacterium tuberculosis complex and directs public health reporting and therapy.
`A31.9`	Mycobacteriosis, unspecified	Used for nontuberculous mycobacterial infections where species identification confirms the specific pathogen.
`R05`	Cough	Common presenting symptom prompting respiratory specimen collection and subsequent AFB testing and identification.
`R50.9`	Fever, unspecified	Systemic symptom that may accompany mycobacterial infection and trigger diagnostic testing.
`J98.4`	Other disorders of lung, not elsewhere classified (including bronchiectasis and chronic infection contexts)	Chronic lung disease predisposes to nontuberculous mycobacterial infection and indicates need for definitive identification.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`87015`	Culture, bacterial; any other source except urine, blood or stool, aerobic, any source except urine (for example: respiratory, tissue)	Often precedes `87118` as culture recovery of organism is required before species-level identification.
`87116`	Culture, mycobacteria; isolation and presumptive identification	Represents the initial culture and presumptive identification step; `87118` performs definitive species identification following `87116`.
`87481`	Infectious agent detection by nucleic acid (DNA or RNA); Mycobacterium tuberculosis complex, amplified probe technique	Molecular identification that may be used as an alternative or adjunct to tests billed under `87118` depending on method.
`87111`	Susceptibility testing for mycobacteria (when performed)	Susceptibility testing is frequently performed after definitive species identification to guide antimicrobial therapy; often part of the subsequent workflow.
`87880`	Infectious agent antigen detection by immunoassay, multiple step (example codes for context)	Rapid antigen or molecular assays may be performed in parallel but are not replacements for species-level identification coded with `87118`.

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Summary & Overview

CPT 87118: Definitive Identification of Acid–Fast Bacilli Isolate