Summary & Overview
CPT 87187: Minimum Lethal Concentration (MLC) Antimicrobial Testing
CPT code 87187 represents the laboratory technical procedure to determine the minimum lethal concentration (MLC) of an antimicrobial agent for a specific culture isolate. This specialized microbiology test provides a quantitative measure of the antibiotic concentration required to kill an organism and is used in clinical care when detailed susceptibility information informs treatment for serious or refractory infections. Nationally, accurate reporting of this code supports clinical decision-making and appropriate coverage and reimbursement for advanced antimicrobial susceptibility testing.
Key payers discussed include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find an overview of clinical context for use of MLC testing, typical sites of service, and the payer landscape relevant to billing and coverage. The publication outlines benchmarks such as utilization and reimbursement patterns where available, summarizes any notable policy updates affecting laboratory testing, and clarifies coding and billing considerations tied to this specialized microbiology service.
This analysis is intended for a national audience of laboratory managers, billing professionals, and policy analysts seeking concise, actionable context about CPT code 87187, its clinical role, and its relevance to payer coverage and laboratory operations.
Billing Code Overview
CPT code 87187 describes the laboratory procedure in which a lab analyst determines the minimum lethal concentration (MLC) for an antimicrobial agent against a specific culture isolate. This test measures the lowest concentration of an antimicrobial that kills the targeted organism and is used to assess susceptibility where minimum inhibitory concentration (MIC) or standard susceptibility tests may not be sufficient.
Service Type: Microbiology laboratory antimicrobial susceptibility testing (MLC determination)
Typical Site of Service: Clinical laboratory or hospital microbiology laboratory
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Clinical & Coding Specifications
Clinical Context
A 68-year-old inpatient with a recent hospitalization for community-acquired pneumonia has a persistent febrile illness and blood cultures that grew a non‑susceptible Gram‑negative organism. The clinical microbiology laboratory isolates the organism and the laboratorian performs antimicrobial susceptibility testing with determination of the minimum lethal concentration (MLC) for one or more antimicrobial agents to guide therapy. Specimen processing occurs in the hospital microbiology laboratory (typical site of service: hospital clinical laboratory or independent diagnostic laboratory). The workflow includes isolate identification (culture), preparation of standardized inoculum, exposure to serial dilutions of the antimicrobial agent, incubation, and assessment of the lowest concentration that results in bacterial death (MLC), with documentation in the laboratory information system and communication of results to the treating infectious disease clinician and antimicrobial stewardship program.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | Use when reporting only the professional interpretation component if the laboratory separates technical and professional components and a physician provides professional interpretation. |
TC |