Summary & Overview
CPT 86171: Complement Fixation Antigen Detection
CPT code 86171 denotes a laboratory procedure that uses complement fixation techniques to detect specific antigens, such as influenza virus antigens. This technical laboratory assay remains relevant for infectious disease identification and public health surveillance, particularly when alternative immunoassays or molecular methods are unavailable or when historical comparability of results is required. Nationally, recognition of this code supports accurate claims processing for laboratory services and informs payer coverage determinations.
Key payers addressed include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise outline of what CPT code 86171 represents, the typical clinical and laboratory context for its use, and the payer landscape relevant to reimbursement and claims adjudication. The publication summarizes benchmark considerations, where available, and highlights policy and billing considerations that commonly affect laboratory technical-component claims. It also provides clinical context for when complement fixation antigen detection may be used relative to other laboratory modalities.
Data not available in the input is noted where applicable; the report focuses on national implications rather than state-specific rules.
Billing Code Overview
CPT code 86171 describes a technical laboratory assay using complement fixation methods to detect the presence of specific antigens, for example influenza virus antigens. The procedure is a laboratory diagnostic test that involves reagents and instrumentation to assess antigen-antibody reactions via complement fixation.
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Service type: Clinical laboratory diagnostic testing (technical component)
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Typical site of service: Hospital laboratories, independent clinical laboratories, and public health laboratory settings
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Clinical & Coding Specifications
Clinical Context
A typical patient is an adult presenting to an outpatient clinic or urgent care during influenza season with acute onset fever, cough, myalgias, and respiratory symptoms. A clinician collects a nasopharyngeal or throat specimen and sends it to the clinical laboratory for antigen detection. In the laboratory, a medical technologist or laboratory analyst performs a complement fixation–based serologic or antigen detection assay to identify the presence of specific viral antigens such as influenza virus. Results are reported back to the ordering clinician to guide antiviral therapy decisions, infection control, and public health reporting. Typical workflow steps include specimen receipt, accessioning, preparation, performance of the complement fixation assay, quality control, result interpretation, and electronic reporting of final results into the chart or laboratory information system.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | When a physician or qualified provider performs interpretation or professional oversight separate from the laboratory technical component |
TC | Technical component | When only the laboratory technical portion of the test is billed by the performing laboratory |