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    v1.0.28
    OpenPayerBilling CodesChemistry ProceduresCPT cpt-84545-urea-nitrogen-clearance-renal-function-test
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    CPT 84545: Urea Nitrogen Clearance (mL/min)

    CPT code 84545 reports a laboratory measurement of urea nitrogen clearance, representing the volume of blood from which urea nitrogen is cleared by the kidneys per minute; this is a quantitative renal clearance test typically performed by a clinical laboratory or hospital lab (service type: laboratory diagnostic test) with the typical site of service being a clinical laboratory or hospital outpatient laboratory.

    For related coverage guidance, see recent payer policy updates: Salivary Hormone Testing, Parathyroid Hormone, Phosphorus, Calcium, and Magnesium Testing, Bone Turnover Markers Testing.

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    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.

    Related CPT Codes

    CPT CodeDescriptionRelationship to This Procedure
    80048Basic metabolic panel (calcium, total)Often ordered concurrently to assess electrolytes and renal function alongside urea clearance testing.
    84830Blood urea nitrogen (BUN)Directly related assay; BUN measurement is required to calculate urea nitrogen clearance.
    82043Creatinine; urineUrine creatinine measurement used when calculating creatinine clearance and timed urine-based assessments.
    82565Creatinine; serumSerum creatinine is commonly ordered with BUN to estimate glomerular filtration rate and interpret urea clearance.
    94640Hemodialysis procedure, dialysis sessionRelevant in workflows where results guide initiation or adjustment of dialysis; performed by dialysis teams.

    Related Modifiers

    9 rows

    ModifierDescriptionWhen to Use
    26Modifier 26 (Professional Component) identifies and bills only the professional portion of a split service — the physician’s interpretation, report, and medical judgment — when the technical…- Use CPT Modifier -26 when you are billing only the professional component (PC) of a split‑bill eligible service—i.e., you performed the physician interpretation, medical judgment and prepared a…
    90Modifier ‑90 (Reference/Outside Laboratory) indicates that a laboratory test was performed by an entity other than the treating or reporting provider. The American Medical Association defines…- Use CPT modifier -90 when a laboratory test is performed by an outside/reference laboratory (an entity other than the treating or reporting physician or qualified professional) and the claim needs…
    91Modifier 91 — “Repeat Clinical Diagnostic Laboratory Test” — is appended when the exact same CPT laboratory test is performed more than once for the same patient on the same day because serial,…- Use modifier 91 when the exact same CPT laboratory test is performed more than once on the same patient on the same date because serial or repeated testing is medically necessary to monitor…
    52Modifier ‑52 (Reduced Services) indicates that a service or procedure was partially reduced or omitted at the provider’s discretion, allowing reporting of the basic procedure number with a qualifier…- Use modifier -52 when a physician or qualified health professional electively reduces or omits part of a procedure or service (for example, performing fewer required views or omitting a portion of…
    53Modifier 53 (Discontinued Procedure) signals that a surgical or diagnostic service was begun by the physician but terminated because of extenuating circumstances that threatened the patient’s…- Use modifier -53 when a physician/qualified healthcare professional has started a surgical or diagnostic procedure (e.g., anesthesia administered, incision or scope insertion) and then discontinues…
    59Modifier 59 indicates a distinct procedural service when two procedures that are not normally billed together are clinically and procedurally separate. The CPT definition (as reiterated by CMS)…- Use modifier -59 to report a distinct procedural service when documentation supports that the procedure reported is not normally billed together with another service on the same day because of a…
    23Modifier -23 (Unusual Anesthesia) is used on anesthesia service CPT codes when a procedure that normally requires no anesthesia or only local anesthesia must be performed under general anesthesia…- Use modifier -23 only on anesthesia CPT codes (00100–01999) when a procedure that normally requires no anesthesia or only local anesthesia must be performed under general anesthesia because of…
    22Modifier –22 (Increased Procedural Services) is used when a reported procedure is substantially more extensive than normally required. The CPT Manual and CMS state it may be appended only when the…- When to use: Append modifier -22 to a procedural CPT code when the service performed is substantially more extensive than the usual service described by that code — i.e., the procedure required…
    76Modifier -76, Repeat Procedure or Service by Same Physician or Other Qualified Health Care Professional, is appended when the same provider performs an identical, medically necessary procedure or…- Use modifier -76 when the same physician or other qualified health care professional performs an identical procedure or service a second (or subsequent) time on the same date of service and the…

    Related Provider Taxonomies

    8 rows

    Taxonomy CodeSpecialtyNotes
    207R00000XInternal Medicine PhysicianA physician who provides long-term, comprehensive care in the office and the hospital, managing both common and complex illness of adolescents, adults…
    208D00000XGeneral Practice PhysicianA physician who specializes in the general practice of diagnosing, treating, and managing patients with a variety of illnesses and conditions.
    207Q00000XFamily Medicine PhysicianFamily Medicine is the medical specialty which is concerned with the total health care of the individual and the family. It is the specialty in breadt…
    332BX2000XOxygen Equipment & Supplies (DME)Suppliers · Durable Medical Equipment & Medical Supplies
    204E00000XOral & Maxillofacial Surgery (D.M.D.)Oral and maxillofacial surgeons are trained to recognize and treat a wide spectrum of diseases, injuries and defects in the head, neck, face, jaws and…
    207PP0204XPediatric Emergency Medicine (Emergency Medicine) PhysicianPediatric Emergency Medicine is a clinical subspecialty that focuses on the care of the acutely ill or injured child in the setting of an emergency de…
    261QR0800XRecovery Care Clinic/CenterAmbulatory Health Care Facilities · Clinic/Center
    261QM1103XMilitary Ambulatory Procedure Visits Operational (Transportable) Clinic/Center"Non-fixed" facilities or distinct parts of a "non-fixed" facility, providing outpatient surgical procedures requiring medically supervised recovery. …

    Related ICD-10-CM Codes

    28 rows

    ICD-10-CM CodeDescription
    B20Human immunodeficiency virus [HIV] disease
    D63.1Anemia in chronic kidney disease
    E08.22Diabetes mellitus due to underlying condition with diabetic chronic kidney disease
    E09.22Drug or chemical induced diabetes mellitus with diabetic chronic kidney disease
    E10.22Type 1 diabetes mellitus with diabetic chronic kidney disease
    E11.22Type 2 diabetes mellitus with diabetic chronic kidney disease
    E78.5Hyperlipidemia, unspecified
    I12.9Hypertensive chronic kidney disease with stage 1 through stage 4 chronic kidney disease, or unspecified chronic kidney disease
    I13.0Hypertensive heart and chronic kidney disease with heart failure and stage 1 through stage 4 chronic kidney disease, or unspecified chronic kidney disease
    I13.11Hypertensive heart and chronic kidney disease without heart failure, with stage 5 chronic kidney disease, or end stage renal disease

    Showing 1–10 of 28

    Related Payer Policy Updates

    Specialty: Endocrinology1 / 3

    10 rows

    PolicyPayerEffective Date
    Salivary Hormone TestingOscar Health2026-10-01
    Parathyroid Hormone, Phosphorus, Calcium, and Magnesium TestingOscar Health2026-10-01
    Bone Turnover Markers TestingOscar Health2026-10-01
    Testosterone — Coverage Criteria for Measurement and MonitoringOscar Health2026-10-01
    Diabetes Mellitus Testing — Coverage CriteriaOscar Health2026-10-01
    Thyroid Disease TestingOscar Health2026-10-01
    Thyroid Disease Testingblue cross blue shield - louisiana2026-09-15
    Thyroid Disease TestingBlue Cross Blue Shield - New Mexico2026-09-04
    Parathyroid Hormone, Phosphorous, Calcium and Magnesium TestingBlue Cross Blue Shield - New Mexico2026-09-04
    Testosterone laboratory testing and managementPremera Bluecross2026-09-04

    Related Codes

    CPT-82009-KETONE-BODIES-QUALITATIVE-TEST

    CPT 82009: Qualitative Ketone Bodies Test

    CPT-82010-QUANTITATIVE-KETONE-BODIES-ASSAY-SERUM-PLASMA

    CPT 82010: Quantitative Ketone Bodies in Serum or Plasma

    CPT-82013-ACETYLCHOLINESTERASE-QUANTITATIVE-ASSAY

    CPT 82013: Quantitative Acetylcholinesterase (Acetylhydrolase) Assay

    CPT-82016-QUALITATIVE-ACYLCARNITINES-METABOLIC-SCREEN

    CPT 82016: Qualitative Acylcarnitines, Plasma/Serum/Urine

    CPT-82017-QUANTITATIVE-ACYLCARNITINE-ANALYSIS

    CPT 82017: Quantitative Acylcarnitine Analysis

    CPT-82024-QUANTITATIVE-CORTICOTROPIN-ACTH-ASSAY

    CPT 82024: Adrenocorticotropic Hormone (ACTH) Quantitative Assay

    CPT-82030-QUANTITATIVE-CAMP-PLASMA-URINE-ASSAY

    CPT 82030: Quantitative cyclic AMP assay on plasma or urine

    CPT-82040-QUANTITATIVE-ALBUMIN-MEASUREMENT

    CPT 82040: Quantitative Albumin Measurement

    CPT-82042-QUANTITATIVE-ALBUMIN-NONBLOOD-FLUID

    CPT 82042: Albumin Quantitation in Non-Blood Body Fluid

    CPT-82043-URINE-ALBUMIN-QUANTITATION-KIDNEY-DISEASE

    CPT 82043: Urine Albumin Quantitative Assay

    Showing 1–10 of 411

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    Frequently Asked Questions

    References

    1. 1.CPT® Codes and Descriptions. AAPC. Retrieved Aug 11, 2026.Maintains the CPT code set's official descriptions and guidelines, licensed from the American Medical Association, used as the definitional source for CPT codes on this page.
    2. 2.HCPCS Quarterly Update. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's quarterly release of HCPCS Level II codes and short/long descriptors, the source for HCPCS code definitions and update history.
    3. 3.ICD-10-CM Full Code List. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's complete ICD-10-CM diagnosis code list, used to cross-reference diagnosis codes associated with this procedure or service.
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