Summary & Overview
CPT 83527: Free (Unbound) Insulin Assay
CPT code 83527 designates a laboratory measurement of free (unbound) insulin in serum, identifying the biologically active fraction of circulating insulin. This test can inform clinical assessment of insulin secretion, insulin resistance, and therapy monitoring in diabetes and endocrine disorders. Nationally, the code is relevant for lab billing, clinical decision support, and payer coverage determinations for endocrine and metabolic evaluations.
Key payers in typical analyses include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of the clinical use of the assay, typical sites of service, and payer considerations where available. The publication outlines common billing modifiers and the role of this quantitative assay in clinical workflows.
The report presents benchmarks and practical context for laboratory managers, billing staff, and clinicians: how the assay is reported using CPT code 83527, where it is usually performed, and how it fits into laboratory-based evaluation of insulin-related conditions. Data not available in the input is noted where applicable.
Billing Code Overview
CPT code 83527 measures free insulin concentration in a serum sample. The test quantifies the portion of circulating insulin that is unbound and biologically active, which is relevant for assessing insulin bioavailability and certain metabolic or endocrine evaluations.
Service type: Clinical laboratory test — quantitative immunoassay/biochemical measurement of free (unbound) insulin.
Typical site of service: Clinical laboratory or hospital laboratory, outpatient laboratory draw, or reference laboratory processing.
Clinical & Coding Specifications
Clinical Context
A 48-year-old outpatient with a history of type 2 diabetes mellitus presents for evaluation of persistent hyperglycemia despite therapy adjustment. The clinician orders laboratory assessment of fasting serum insulin, including free insulin measurement to evaluate biologically active insulin levels and investigate possible endogenous hyperinsulinemia or exogenous insulin interference. A phlebotomy technician collects a serum sample, labels it with patient identifiers and order information, and sends it to the clinical chemistry laboratory. The laboratory analyst performs specimen accessioning, centrifugation, and assay—typically an immunoassay or mass spectrometry method validated to quantify unbound (free) insulin concentration. Results are verified by a laboratory professional, documented in the electronic medical record, and released to the ordering provider for interpretation and treatment planning. Typical site of service is an outpatient clinic or outpatient laboratory draw station; testing may also occur in an inpatient hospital laboratory when clinically indicated.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | When reporting the professional interpretation or supervision component separate from the technical laboratory work, if applicable in certain billing arrangements. |
59 |