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.