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    v1.0.28
    OpenPayerBilling CodesChemistry ProceduresCPT cpt-83945-urinary-oxalate-quantitative
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    CPT 83945: Urine Oxalate Measurement

    CPT code 83945 describes a laboratory assay for measurement of oxalate concentration, commonly performed on a 24-hour urine specimen to evaluate urinary oxalate excretion; the service is a clinical chemistry laboratory test typically provided in clinical laboratories or hospital lab settings for metabolic stone evaluation and related metabolic assessments.

    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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    Clinical & Coding Specifications

    Clinical Context

    A typical patient is an adult referred to a clinical laboratory by a urologist or nephrologist for evaluation of recurrent nephrolithiasis (kidney stones) or unexplained hematuria. The clinician orders a 24-hour urine collection to quantify urinary oxalate excretion after initial imaging (CT or ultrasound) or stone analysis demonstrates calcium oxalate composition or when metabolic workup is indicated. The patient receives instructions for a complete 24-hour urine collection, dietary guidance to avoid excessive oxalate-rich foods during collection if required, and documentation of collection start and stop times. The specimen is delivered to the outpatient laboratory or hospital clinical chemistry department; the lab analyst performs the quantitative oxalate assay using an enzymatic or ion chromatography method. Results are reported to the ordering provider and used to guide dietary counseling, medical therapy (e.g., thiazide diuretics, citrate supplementation), or further metabolic evaluation. Typical sites of service include outpatient hospital laboratory, independent clinical laboratory, or hospital-based clinical chemistry lab within an ambulatory or inpatient facility.

    Related CPT Codes

    CPT CodeDescriptionRelationship to This Procedure
    80053Comprehensive metabolic panel (CMP)Performed to assess renal function and electrolytes during metabolic stone workup; often ordered alongside oxalate measurement
    82570Creatinine; urine (quantitative)Used to normalize 24-hour urine analytes to creatinine or verify collection completeness
    82520Urine sodium; quantitativeAssesses dietary sodium which influences urinary calcium and stone risk in metabolic evaluation
    83945Oxalate; urine (quantitative)Primary procedure measuring urinary oxalate excretion to evaluate calcium oxalate stone risk
    81025Urine pregnancy test, by dipstick or tablet reagent; non-automatedOften performed prior to imaging or certain interventions in reproductive-age patients (contextual adjunct)

    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…
    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…
    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…

    Related Provider Taxonomies

    8 rows

    Taxonomy CodeSpecialtyNotes
    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…
    208000000XPediatrics PhysicianA pediatrician is concerned with the physical, emotional and social health of children from birth to young adulthood. Care encompasses a broad spectru…
    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…
    224900000XMastectomy FitterAn individual trained in the fitting and adjusting of breast prostheses and management of post-mastectomy prostheses services.
    207SG0202XClinical Biochemical Genetics PhysicianA clinical biochemical geneticist demonstrates competence in performing and interpreting biochemical analyses relevant to the diagnosis and management…
    207YS0123XFacial Plastic Surgery PhysicianAn otolaryngologist who specializes in facial plastic surgery.
    364SP2800XPerioperative Clinical Nurse SpecialistPhysician Assistants & Advanced Practice Nursing Providers · Clinical Nurse Specialist
    311500000XAlzheimer Center (Dementia Center)A freestanding facility or special care unit of a long term care facility focusing on patient care of individuals diagnosed with dementia or Alzheimer…

    Related ICD-10-CM Codes

    28 rows

    ICD-10-CM CodeDescription
    E03.9Hypothyroidism, unspecified
    E79.0Hyperuricemia without signs of inflammatory arthritis and tophaceous disease
    E83.51Hypocalcemia
    E86.0Dehydration
    K80.00Calculus of gallbladder with acute cholecystitis without obstruction
    K80.20Calculus of gallbladder without cholecystitis without obstruction
    N13.2Hydronephrosis with renal and ureteral calculous obstruction
    N20.0Calculus of kidney
    N20.1Calculus of ureter
    N20.2Calculus of kidney with calculus of ureter

    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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