Summary & Overview
CPT 84545: Urea Nitrogen Clearance (Renal Function Test)
Headline: CPT code 84545 defines a laboratory assay that estimates renal clearance of urea nitrogen, a key measure of kidney excretory function.
Lead: CPT code 84545 represents a quantitative laboratory test that calculates the volume of blood filtered of urea nitrogen by the kidneys per minute. The measure provides clinicians with information about renal excretory performance and can influence diagnosis and management of kidney disease.
Why it matters: Nationally, laboratory measures of kidney function are fundamental to nephrology care, acute hospital management, and medication dosing decisions. Standardized reporting for CPT code 84545 supports consistent billing, clinical interpretation, and comparative benchmarking across payers and laboratory providers.
Key payers covered: Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare.
What readers will learn: The publication outlines the clinical context and laboratory setting for CPT code 84545, summarizes common billing modifiers (listed separately), and provides benchmarks and policy-relevant considerations where available. It also details typical sites of service and service type to aid coding and billing workflows.
Scope: This summary addresses the national clinical and billing context for CPT code 84545. Data not available in the input for specific payer reimbursement rates, utilization frequencies, associated taxonomies, ICD-10 diagnoses, and related codes.
Billing Code Overview
CPT code 84545 describes a laboratory measurement that calculates the urea nitrogen clearance rate, an estimate of the volume of blood cleared of urea nitrogen by the kidneys per minute. This test is a quantitative renal function assay used to evaluate glomerular filtration related to urea nitrogen handling.
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Service type: Clinical laboratory renal function test
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Typical site of service: Hospital laboratory or independent clinical laboratory
Data not available in the input for payers, associated taxonomies, ICD-10 diagnoses, related codes, and service line.
Clinical & Coding Specifications
Clinical Context
A typical patient is an adult with chronic kidney disease or suspected acute kidney injury who requires assessment of renal function. The clinician orders a blood test to calculate the glomerular filtration rate of urea nitrogen or a clearance estimate to quantify renal urea clearance per minute. The patient presents to an outpatient laboratory, hospital phlebotomy station, or inpatient ward; a venous blood sample (and sometimes timed urine collection) is obtained by a phlebotomist or nurse and sent to the clinical laboratory. The laboratory analyst performs the assay, including measurement of blood urea nitrogen (BUN) and any required calculations to derive the urea nitrogen clearance rate (volume per minute). Results are reported to the ordering provider (nephrologist, hospitalist, or primary care clinician) and documented in the medical record to guide medication dosing, dialysis planning, or further diagnostic evaluation.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | Use when billing only the professional interpretation component if split billing applies. |
TC | Technical component | Use when billing only the laboratory/technical component (equipment, technician) of the test. |