Summary & Overview
CPT 82042: Quantitative Albumin in Non-Blood Body Fluid
CPT code 82042 represents a quantitative laboratory assay that measures albumin in a measured, timed, or random specimen when the specimen is a fluid other than blood, serum, plasma, or urine. This test is clinically important for evaluating protein content of non-blood body fluids such as pleural, peritoneal, synovial, or cerebrospinal fluid and can inform diagnoses like effusions, infections, and inflammatory or neoplastic processes. Nationally, the code matters for clinical laboratories and payers because it identifies a distinct laboratory service with implications for coverage, billing, and laboratory workflow.
Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find an overview of what CPT code 82042 denotes, typical clinical contexts and sites of service, and what to expect in terms of payer coverage considerations. The publication summarizes common modifiers associated with laboratory services, highlights where data is available or missing, and provides benchmark-oriented content for laboratory billing teams and revenue cycle stakeholders. The material is intended to clarify the clinical and billing scope of CPT code 82042 and to serve as a concise reference for national stakeholders.
Billing Code Overview
CPT code 82042 describes a laboratory quantitation of albumin in a measured, timed, or random specimen where the specimen is a fluid source other than blood, serum, plasma, or urine. The service reports the measured albumin concentration from a non-blood body fluid and is used when the laboratory analyst performs the quantitative assay and documents the result.
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Service type: Clinical laboratory quantitative assay
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Typical site of service: Hospital laboratory, independent clinical laboratory, or other outpatient laboratory settings where non-blood fluid specimens (for example, pleural, peritoneal, synovial, cerebrospinal fluid) are collected and analyzed
Clinical & Coding Specifications
Clinical Context
A typical patient is an adult admitted to an inpatient ward or presenting to an outpatient specialty clinic (e.g., nephrology, infectious disease, oncology) with a suspected or known serous fluid abnormality such as pleural effusion, ascites, or cerebrospinal fluid change. A clinician orders fluid analysis including 82042 when quantitation of albumin in a non-blood fluid specimen (for example pleural, peritoneal, synovial, or cerebrospinal fluid) is required to assess protein dynamics, guide differential diagnosis (transudate vs exudate), monitor nutritional/protein status, or calculate gradient measurements (e.g., serum-ascites albumin gradient).
Workflow:
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A clinician collects a non-blood fluid specimen (random, timed, or measured) using standard sterile technique in the appropriate clinical setting (inpatient, outpatient clinic, emergency department, or procedure suite).
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The specimen is labeled and transported to the clinical laboratory with accompanying order for
82042and any other requested fluid studies. -
Laboratory personnel perform the albumin quantitation using validated methods (e.g., immunoassay) and document the numeric concentration and units in the laboratory information system.
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Results are reported to the ordering provider and integrated into the patient record to support clinical interpretation (e.g., calculation of gradients or comparison to serum albumin).