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    v1.0.28
    OpenPayerBilling CodesChemistry ProceduresCPT cpt-84520-blood-urea-nitrogen-quantitative
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    CPT 84520: Blood Urea Nitrogen (BUN) Quantitative Test

    CPT code 84520 describes a laboratory quantitative measurement of blood urea nitrogen (BUN) performed on a patient specimen; this is a clinical chemistry diagnostic test used to assess renal function and nitrogen balance. Service type: laboratory test / clinical chemistry. Typical site of service: clinical laboratory or hospital laboratory where a blood specimen is collected and analyzed.

    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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    Table of contents

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    • Billing CodesCPT, HCPCS, DRG & more
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    Clinical & Coding Specifications

    Clinical Context

    A 58-year-old male with hypertension and type 2 diabetes presents to the outpatient clinic for routine monitoring and evaluation for fatigue and mild peripheral edema. The clinician orders basic metabolic laboratory panels to assess renal function and electrolyte status. As part of that panel, a serum blood urea nitrogen (BUN) test is performed. A phlebotomist collects a venous blood specimen in the clinic laboratory; the specimen is sent to the hospital core laboratory where a clinical laboratory scientist or lab analyst runs the quantitative BUN assay using automated chemistry analyzers. Results are reviewed by the ordering provider to assess renal perfusion, hydration status, and to aid interpretation of creatinine and estimated glomerular filtration rate (eGFR). Typical workflow steps: patient registration and order entry, specimen collection by phlebotomy, specimen labeling and transport to the laboratory, specimen accessioning, analysis by laboratory personnel, result verification, and result reporting to the ordering provider. Typical sites of service include outpatient clinic laboratories, hospital inpatient laboratories, and independent clinical pathology laboratories.

    Related CPT Codes

    CPT CodeDescriptionRelationship to This Procedure
    80048Basic metabolic panel (Calcium, total)Common panel that includes BUN alongside electrolytes and creatinine; often ordered together.
    80053Comprehensive metabolic panelBroader metabolic profile that includes BUN; frequently performed in workflows that include BUN measurement.
    82565Creatinine; bloodCommonly ordered with BUN to assess renal function and calculate BUN/creatinine ratio.
    84132Uric acid; serumMay be ordered in metabolic assessments when evaluating renal function or metabolic disease.
    99213Office or other outpatient visit, established patientTypical visit code for the clinician encounter during which the BUN is ordered and results reviewed.

    Related Modifiers

    6 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…
    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…
    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
    207L00000XAnesthesiology PhysicianAn anesthesiologist is trained to provide pain relief and maintenance, or restoration, of a stable condition during and immediately following an opera…
    207LP2900XPain Medicine (Anesthesiology) PhysicianAn anesthesiologist who provides a high level of care, either as a primary physician or consultant, for patients experiencing problems with acute, chr…
    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…
    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…
    207RC0000XCardiovascular Disease PhysicianAn internist who specializes in diseases of the heart and blood vessels and manages complex cardiac conditions such as heart attacks and life-threaten…
    2080S0012XPediatric Sleep Medicine PhysicianA Pediatrician who practices Sleep Medicine is certified in the subspecialty of sleep medicine and specializes in the clinical assessment, physiologic…
    343800000XSecured Medical Transport (VAN)A public or privately owned transportation service with vehicles, specially equipped to provide enhanced safety, security and passenger restraint, and…
    207QS0010XSports Medicine (Family Medicine) PhysicianA family medicine physician that is trained to be responsible for continuous care in the field of sports medicine, not only for the enhancement of hea…

    Related ICD-10-CM Codes

    27 rows

    ICD-10-CM CodeDescription
    A41.9Sepsis, unspecified organism
    B96.20Unspecified Escherichia coli [E. coli] as the cause of diseases classified elsewhere
    D50.9Iron deficiency anemia, unspecified
    D63.8Anemia in other chronic diseases classified elsewhere
    E10.22Type 1 diabetes mellitus with diabetic chronic kidney disease
    E11.22Type 2 diabetes mellitus with diabetic chronic kidney disease
    E66.9Obesity, unspecified
    E78.5Hyperlipidemia, unspecified
    E86.0Dehydration
    E86.1Hypovolemia

    Showing 1–10 of 27

    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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