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    v1.0.28
    OpenPayerBilling CodesChemistry ProceduresCPT cpt-82140-ammonia-blood-plasma-testing
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    CPT 82140: Ammonia Measurement in Blood/Plasma

    CPT code 82140 describes a laboratory quantitative measurement of ammonia in blood, plasma, or other body fluids used to evaluate suspected metabolic or infectious processes; this is a clinical laboratory test typically performed in a hospital laboratory, reference laboratory, or clinical chemistry setting and reported as a discrete chemistry service for specimens collected in inpatient, outpatient, or emergency department settings.

    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 a hospitalized adult or pediatric patient presenting with altered mental status, unexplained encephalopathy, suspected hepatic failure, inborn errors of metabolism, or recent severe infection/sepsis. The clinician orders an ammonia measurement (82140) when hyperammonemia is suspected to evaluate for hepatic dysfunction, portosystemic shunting, urea cycle disorder, or metabolic decompensation. Blood (usually plasma collected on ice and delivered rapidly to the lab) or other body fluids are obtained by phlebotomy; the specimen is processed in the clinical laboratory where an automated analyzer or enzymatic assay measures ammonia concentration. Results are reported to the ordering provider for correlation with liver function tests, venous/arterial blood gases, lactate, and clinical exam to guide diagnostic evaluation and acute management decisions. Typical sites of service include hospital inpatient wards, emergency departments, intensive care units, and specialty clinics (e.g., hepatology, metabolic disorders clinic).

    Related CPT Codes

    CPT CodeDescriptionRelationship to This Procedure
    80053Comprehensive metabolic panelOften ordered alongside ammonia to evaluate liver and metabolic function.
    82040Albumin; serum, plasma or whole bloodOrdered with ammonia when assessing liver synthetic function.
    84460Thyroid stimulating hormone (TSH)Ordered in altered mental status workups and metabolic evaluations.
    85025Complete blood count (CBC) with automated differentialRoutine concurrent testing for infection, anemia, or sepsis evaluation.
    83655Lactic acid (lactate)Often performed with ammonia in critically ill patients to assess metabolic stress and perfusion.

    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…
    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…
    77Modifier 77 indicates that a previously performed procedure or service was legitimately repeated by a different physician or other qualified health care professional. The AMA’s CPT definition…- Use modifier 77 when a basic procedure or service already performed is repeated by a different physician or other qualified health care professional (for example, a second provider independently…
    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…
    24Modifier 24 denotes an unrelated evaluation and management (E/M) service performed by the same physician or qualified healthcare professional during a postoperative global period. Per CPT guidance,…- Use modifier 24 when you report an evaluation and management (E/M) service performed by the same physician or same-specialty group during a procedure’s postoperative global period that is unrelated…

    Related Provider Taxonomies

    8 rows

    Taxonomy CodeSpecialtyNotes
    208000000XPediatrics PhysicianA pediatrician is concerned with the physical, emotional and social health of children from birth to young adulthood. Care encompasses a broad spectru…
    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…
    207L00000XAnesthesiology PhysicianAn anesthesiologist is trained to provide pain relief and maintenance, or restoration, of a stable condition during and immediately following an opera…
    207K00000XAllergy & Immunology PhysicianAn allergist-immunologist is trained in evaluation, physical and laboratory diagnosis, and management of disorders involving the immune system. Select…
    207QA0401XAddiction Medicine (Family Medicine) PhysicianA family medicine physician who specializes in the diagnosis and treatment of addictions.
    2083P0011XUndersea and Hyperbaric Medicine (Preventive Medicine) PhysicianA specialist who treats decompression illness and diving accident cases and uses hyperbaric oxygen therapy to treat such conditions as carbon monoxide…
    261QR0404XCardiac Rehabilitation Clinic/CenterAmbulatory Health Care Facilities · Clinic/Center
    1835S0206XSolid Organ Transplant PharmacistA licensed pharmacist who has demonstrated specialized knowledge and skill delivering direct patient care and the safe and effective use of medication…

    Related ICD-10-CM Codes

    25 rows

    ICD-10-CM CodeDescription
    A41.9Sepsis, unspecified organism
    B19.20Unspecified viral hepatitis C without hepatic coma
    B20Human immunodeficiency virus [HIV] disease
    B95.61Methicillin susceptible Staphylococcus aureus infection as the cause of diseases classified elsewhere
    E02Subclinical iodine-deficiency hypothyroidism
    E53.8Deficiency of other specified B group vitamins
    E70.0Classical phenylketonuria
    E70.1Other hyperphenylalaninemias
    E83.110Hereditary hemochromatosis
    E83.118Other hemochromatosis

    Showing 1–10 of 25

    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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