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    v1.0.30
    OpenPayerBilling CodesChemistry ProceduresCPT cpt-83518-single-step-immunoassay-semiquantitative-test
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    CPT 83518: Immunoassay, Single-Step Analyte Detection

    CPT code 83518 describes a laboratory immunoassay procedure performed by a lab analyst to detect or provide a semiquantitative estimate of an analyte using a single-step method (for example, reagent strip) that allows little room for error in reading and reporting results; service type: clinical laboratory immunoassay testing; typical site of service: clinical laboratory or point-of-care setting.

    For related coverage guidance, see recent payer policy updates: Diabetic Supplies, Radiofrequency Ablation for Thyroid Nodules, Continuous Glucose Monitoring and Insulin Delivery for Managing Diabetes (for Idaho Only).

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    Table of contents

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    Clinical & Coding Specifications

    Clinical Context

    A 45-year-old patient presents to an outpatient clinic reporting recent onset of urinary frequency and dysuria. The clinician collects a clean-catch urine specimen and sends a portion to the onsite laboratory for a rapid, single-step immunoassay performed with a reagent strip to detect a target analyte semiquantitatively. The laboratory analyst performs 83518 to evaluate for the presence of the analyte; results are read directly from the strip and recorded in the patient chart. The typical workflow includes specimen accessioning, label verification, performance of the single-step immunoassay by trained laboratory staff, immediate interpretation of strip color change or instrument readout, documentation of results in the laboratory information system, and communication of positive or equivocal findings to the ordering clinician for clinical correlation and possible further testing (e.g., culture, reflex molecular testing). Typical site of service is outpatient clinic or physician office with point-of-care testing capability; can also be performed in hospital laboratory or urgent care where single-step immunoassays are used for rapid screening.

    Related CPT Codes

    CPT CodeDescriptionRelationship to This Procedure
    81002Urinalysis, by dip stick or tablet reagent; without microscopyOften performed alongside single-step immunoassays to assess urine parameters that correlate with analyte results.
    83986Drug test, qualitative, multiple classes, any number of drug classes; immunoassay screensUsed when broader drug screening by immunoassay is required beyond a single-analyte strip.
    87086Culture, bacterial; urine, quantitative, colony countPerformed after a positive screening immunoassay for suspected urinary tract infection to identify organism and susceptibilities.
    87491Infectious agent antigen detection by immunoassay, direct probe techniquePerformed when confirmation of a specific infectious antigen is needed following a rapid screen.
    86003Antibody; qualitative or semiquantitative, single procedure, each reagent strip testRelated semiquantitative single-step strip assays for antibody detection in other specimen types.

    Related Modifiers

    5 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…
    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…
    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…

    Related Provider Taxonomies

    8 rows

    Taxonomy Code
    207P00000X
    208000000X
    363LP0808X
    163W00000X
    208D00000X
    364SX0200X
    213ES0103X
    171WV0202X

    Related ICD-10-CM Codes

    28 rows

    ICD-10-CM CodeDescription
    A09Infectious gastroenteritis and colitis, unspecified
    B34.9Viral infection, unspecified
    E03.9Hypothyroidism, unspecified
    E11.65Type 2 diabetes mellitus with hyperglycemia
    E11.9Type 2 diabetes mellitus without complications
    E78.5Hyperlipidemia, unspecified
    E87.6Hypokalemia
    I10Essential (primary) hypertension
    I48.91Unspecified atrial fibrillation
    J06.9Acute upper respiratory infection, unspecified

    Showing 1–10 of 28

    Related Payer Policy Updates

    Specialty: Endocrinology1 / 3

    10 rows

    PolicyPayerEffective Date
    Diabetic SuppliesCigna2026-10-15
    Radiofrequency Ablation for Thyroid NodulesCigna2026-10-15
    Continuous Glucose Monitoring and Insulin Delivery for Managing Diabetes (for Idaho Only)UnitedHealthcare2026-10-01
    Tzield (teplizumab-mzwv) CoverageUnitedHealthcare2026-10-01
    Continuous Glucose Monitoring and Insulin Delivery for Managing Diabetes (for Indiana Only)UnitedHealthcare2026-10-01
    Medical Necessity Guidelines Insulin PumpsMass General Brigham Health Plan2026-10-01
    Medical Necessity Guidelines: Continuous Glucose MonitorsMass General Brigham Health Plan2026-10-01
    Continuous Glucose MonitoringAmbetter Nevada2026-10-01
    Salivary Hormone TestingOscar Health2026-10-01
    Parathyroid Hormone, Phosphorus, Calcium, and Magnesium TestingOscar Health2026-10-01

    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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