CPT 83520: Immunoassay for Non-Infectious Analytes

CPT code 83520 describes a laboratory immunoassay procedure in which the lab analyst measures a non-infectious-agent analyte (not an infectious agent antibody or antigen) using immunoassay methodology; it is used when no more specific CPT code exists for that analyte. Service type: laboratory diagnostic testing (immunoassay). Typical site of service: clinical laboratory or hospital laboratory (specimen received and processed in a lab setting).

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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CPT 83520: Immunoassay for Non-Infectious Analytes

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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Get alerted when payer policies referencing 83520 are released or updated.

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Clinical & Coding Specifications

Clinical Context

A middle-aged outpatient presents to the ambulatory laboratory at a hospital-owned pathology service with nonspecific symptoms such as fatigue and weight loss. The clinician orders an immunoassay to measure a non-infectious analyte (for example, a therapeutic drug level, hormone, or tumor marker) for which there is no analyte-specific CPT code. A phlebotomist collects blood using standard venipuncture; the specimen is labeled and sent to the core immunology/chemistry laboratory. A medical technologist performs an immunoassay using instrument platform-specific reagents and measures the analyte concentration. The laboratory documents analytic method, calibration, controls, and result interpretation in the patient record. Billing uses 83520 when the test meets immunoassay methodology criteria and no more specific CPT code exists. Typical site of service is an outpatient clinical laboratory or hospital laboratory; the service type is a laboratory clinical diagnostic immunoassay measuring a non-infectious analyte.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`80053`	Comprehensive metabolic panel	Common concurrent chemistry panel that may be ordered with immunoassays for clinical correlation
`81002`	Urinalysis, non-automated, without microscopy	May be ordered in parallel for evaluation of systemic disease affecting analyte interpretation
`84443`	Thyroid stimulating hormone (TSH)	Example of a specific immunoassay code; used when a specific analyte has its own CPT rather than `83520`
`83516`	Immunoassay for infectious agent antigen detection (distinct)	Related methodology but for infectious antigens; differentiates infectious vs non-infectious analytes when coding
`88305`	Level IV surgical pathology, gross and microscopic examination	May be part of the broader diagnostic workflow when tissue correlation is needed

Related Modifiers

5 rows

Modifier	Description	When to Use
26	Modifier 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…
59	Modifier 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…
90	Modifier ‑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…
91	Modifier 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…
P4	Modifier P4 indicates the patient is ASA Physical Status IV — a patient with severe systemic disease that is a constant threat to life. It is assigned by the anesthesia provider and must be supported…	- When to apply: Use modifier P4 only on anesthesia CPT codes (00100–01999) to indicate ASA Physical Status IV — a patient with severe systemic disease that is a constant threat to life (examples:…

Related Provider Taxonomies

8 rows

Taxonomy Code	Specialty	Notes
208000000X	Pediatrics Physician	A pediatrician is concerned with the physical, emotional and social health of children from birth to young adulthood. Care encompasses a broad spectru…
207R00000X	Internal Medicine Physician	A physician who provides long-term, comprehensive care in the office and the hospital, managing both common and complex illness of adolescents, adults…
363LA2200X	Adult Health Nurse Practitioner	Physician Assistants & Advanced Practice Nursing Providers · Nurse Practitioner
207K00000X	Allergy & Immunology Physician	An allergist-immunologist is trained in evaluation, physical and laboratory diagnosis, and management of disorders involving the immune system. Select…
207L00000X	Anesthesiology Physician	An anesthesiologist is trained to provide pain relief and maintenance, or restoration, of a stable condition during and immediately following an opera…
225XR0403X	Driving and Community Mobility Occupational Therapist	Occupational therapists can optimize and prolong an older driver's ability to drive safely and ease the transition to other forms of transportation if…
103TH0100X	Health Service Psychologist	A psychologist, certified/licensed at the independent practice level in his/her state, who is duly trained and experienced in the delivery of direct, …
207YX0901X	Otology & Neurotology Physician	An otolaryngologist who treats diseases of the ear and temporal bone, including disorders of hearing and balance. The additional training in otology a…

Related ICD-10-CM Codes

27 rows

ICD-10-CM Code	Description
A41.9	Sepsis, unspecified organism
B20	Human immunodeficiency virus [HIV] disease
D50.9	Iron deficiency anemia, unspecified
D64.9	Anemia, unspecified
E03.9	Hypothyroidism, unspecified
E11.9	Type 2 diabetes mellitus without complications
E66.9	Obesity, unspecified
E78.5	Hyperlipidemia, unspecified
F32.A	Depression, unspecified
G47.33	Obstructive sleep apnea (adult) (pediatric)

Showing 1–10 of 27

Related Payer Policy Updates

Specialty: Endocrinology1 / 3

10 rows

Policy	Payer	Effective Date
Salivary Hormone Testing	Oscar Health	2026-10-01
Parathyroid Hormone, Phosphorus, Calcium, and Magnesium Testing	Oscar Health	2026-10-01
Bone Turnover Markers Testing	Oscar Health	2026-10-01
Testosterone — Coverage Criteria for Measurement and Monitoring	Oscar Health	2026-10-01
Thyroid Disease Testing	Oscar Health	2026-10-01
Diabetes Mellitus Testing — Coverage Criteria	Oscar Health	2026-10-01
Thyroid Disease Testing	blue cross blue shield - louisiana	2026-09-15
Thyroid Disease Testing	Blue Cross Blue Shield - New Mexico	2026-09-04
Parathyroid Hormone, Phosphorous, Calcium and Magnesium Testing	Blue Cross Blue Shield - New Mexico	2026-09-04
Testosterone laboratory testing and measurement (coverage criteria)	Premera Bluecross	2026-09-04

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

Frequently Asked Questions

References

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.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.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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Trek Health powers OpenPayer with a leading commercial payer intelligence platform, seamlessly converting fragmented payer data into actionable insights for provider organizations.

Trek Health ingests and normalizes Transparency in Coverage data and payer policy updates to give provider organizations a clear view of how commercial reimbursement behaves across markets, payers, and services. Our platform transforms raw payer disclosures into structured intelligence that supports contract evaluation, payer negotiations, and service line strategy. By combining market benchmarks with ongoing policy visibility, Trek helps teams identify variability, risk, and opportunity in commercial reimbursement. The result is faster insight, stronger negotiating positions, and more informed financial decisions.

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Clinical & Coding Specifications

Clinical Context

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`80053`	Comprehensive metabolic panel	Common concurrent chemistry panel that may be ordered with immunoassays for clinical correlation
`81002`	Urinalysis, non-automated, without microscopy	May be ordered in parallel for evaluation of systemic disease affecting analyte interpretation
`84443`	Thyroid stimulating hormone (TSH)	Example of a specific immunoassay code; used when a specific analyte has its own CPT rather than `83520`
`83516`	Immunoassay for infectious agent antigen detection (distinct)	Related methodology but for infectious antigens; differentiates infectious vs non-infectious analytes when coding
`88305`	Level IV surgical pathology, gross and microscopic examination	May be part of the broader diagnostic workflow when tissue correlation is needed

Related Modifiers

5 rows

Modifier	Description	When to Use
26	Modifier 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…
59	Modifier 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…
90	Modifier ‑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…
91	Modifier 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…
P4	Modifier P4 indicates the patient is ASA Physical Status IV — a patient with severe systemic disease that is a constant threat to life. It is assigned by the anesthesia provider and must be supported…	- When to apply: Use modifier P4 only on anesthesia CPT codes (00100–01999) to indicate ASA Physical Status IV — a patient with severe systemic disease that is a constant threat to life (examples:…

Related Provider Taxonomies

8 rows

Taxonomy Code	Specialty	Notes
208000000X	Pediatrics Physician	A pediatrician is concerned with the physical, emotional and social health of children from birth to young adulthood. Care encompasses a broad spectru…
207R00000X	Internal Medicine Physician	A physician who provides long-term, comprehensive care in the office and the hospital, managing both common and complex illness of adolescents, adults…
363LA2200X	Adult Health Nurse Practitioner	Physician Assistants & Advanced Practice Nursing Providers · Nurse Practitioner
207K00000X	Allergy & Immunology Physician	An allergist-immunologist is trained in evaluation, physical and laboratory diagnosis, and management of disorders involving the immune system. Select…
207L00000X	Anesthesiology Physician	An anesthesiologist is trained to provide pain relief and maintenance, or restoration, of a stable condition during and immediately following an opera…
225XR0403X	Driving and Community Mobility Occupational Therapist	Occupational therapists can optimize and prolong an older driver's ability to drive safely and ease the transition to other forms of transportation if…
103TH0100X	Health Service Psychologist	A psychologist, certified/licensed at the independent practice level in his/her state, who is duly trained and experienced in the delivery of direct, …
207YX0901X	Otology & Neurotology Physician	An otolaryngologist who treats diseases of the ear and temporal bone, including disorders of hearing and balance. The additional training in otology a…

Related ICD-10-CM Codes

27 rows

ICD-10-CM Code	Description
A41.9	Sepsis, unspecified organism
B20	Human immunodeficiency virus [HIV] disease
D50.9	Iron deficiency anemia, unspecified
D64.9	Anemia, unspecified
E03.9	Hypothyroidism, unspecified
E11.9	Type 2 diabetes mellitus without complications
E66.9	Obesity, unspecified
E78.5	Hyperlipidemia, unspecified
F32.A	Depression, unspecified
G47.33	Obstructive sleep apnea (adult) (pediatric)

Showing 1–10 of 27

Related Payer Policy Updates

Specialty: Endocrinology1 / 3

10 rows

Policy	Payer	Effective Date
Salivary Hormone Testing	Oscar Health	2026-10-01
Parathyroid Hormone, Phosphorus, Calcium, and Magnesium Testing	Oscar Health	2026-10-01
Bone Turnover Markers Testing	Oscar Health	2026-10-01
Testosterone — Coverage Criteria for Measurement and Monitoring	Oscar Health	2026-10-01
Thyroid Disease Testing	Oscar Health	2026-10-01
Diabetes Mellitus Testing — Coverage Criteria	Oscar Health	2026-10-01
Thyroid Disease Testing	blue cross blue shield - louisiana	2026-09-15
Thyroid Disease Testing	Blue Cross Blue Shield - New Mexico	2026-09-04
Parathyroid Hormone, Phosphorous, Calcium and Magnesium Testing	Blue Cross Blue Shield - New Mexico	2026-09-04
Testosterone laboratory testing and measurement (coverage criteria)	Premera Bluecross	2026-09-04

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

Frequently Asked Questions

References

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.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.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.

Published by

Trek Health powers OpenPayer with a leading commercial payer intelligence platform, seamlessly converting fragmented payer data into actionable insights for provider organizations.

OpenPayer

CPT 83520: Immunoassay for Non-Infectious Analytes

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OpenPayer

CPT 83520: Immunoassay for Non-Infectious Analytes

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Clinical & Coding Specifications

Clinical Context

Related CPT Codes

Related Modifiers

Related Provider Taxonomies

Related ICD-10-CM Codes

Related Payer Policy Updates

Related Codes

References

Clinical & Coding Specifications

Clinical Context

Related CPT Codes

Related Modifiers

Related Provider Taxonomies

Related ICD-10-CM Codes

Related Payer Policy Updates

Related Codes

References

CPT 83520: Immunoassay for Non-Infectious Analytes

Sign up for cpt 83520 policy alerts

CPT 83520: Immunoassay for Non-Infectious Analytes

Sign up for cpt 83520 policy alerts

Clinical & Coding Specifications

Clinical Context

Related CPT Codes

Related Modifiers

Related Provider Taxonomies

Related ICD-10-CM Codes

Related Payer Policy Updates

Related Codes

When should I use CPT 83520 instead of a specific immunoassay CPT code?

What modifiers are commonly used with 83520 and when do they apply?

Where is CPT 83520 typically performed and what is the clinical workflow?

How does 83520 relate to other laboratory CPT codes like 84443 or 80053?

Which payers commonly cover CPT 83520 and why is this code important for reimbursement?

References

Clinical & Coding Specifications

Clinical Context

Related CPT Codes

Related Modifiers

Related Provider Taxonomies

Related ICD-10-CM Codes

Related Payer Policy Updates

Related Codes

When should I use CPT 83520 instead of a specific immunoassay CPT code?

What modifiers are commonly used with 83520 and when do they apply?

Where is CPT 83520 typically performed and what is the clinical workflow?

How does 83520 relate to other laboratory CPT codes like 84443 or 80053?

Which payers commonly cover CPT 83520 and why is this code important for reimbursement?

References