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HCPCS G0475: HIV Antigen/Antibody Combination Assay, Screening

HCPCS Level II code G0475 designates an HIV antigen/antibody combination assay used for screening individuals for HIV infection. This laboratory screening code is important for public health and preventive care, as combined antigen/antibody tests increase early detection of HIV compared with antibody-only tests. Nationally, such screening supports timely linkage to care and reduces transmission through earlier diagnosis.

Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find an overview of coverage considerations, common billing modifiers, and where the service is typically furnished. The publication outlines typical reimbursement benchmarking elements, coding and billing context for laboratory screening services, and potential policy updates affecting coverage and payment for combination HIV assays.

This summary equips clinicians, billing professionals, and policy analysts with the clinical context, payer landscape, and coding fundamentals relevant to G0475. Data not available in the input will be noted where applicable in detailed sections.

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Billing Code Overview

HCPCS Level II code G0475 represents an HIV antigen/antibody combination assay used for screening patients for HIV infection. This code describes a laboratory assay that detects both HIV antigen and HIV antibodies in a single combined test.

Service Type: Laboratory screening assay

Typical Site of Service: Clinical laboratory or outpatient facility

Data not available in the input.

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HCPCS G0475: HIV Antigen/Antibody Combination Assay, Screening

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Billing Code Overview

Service Type: Laboratory screening assay

Typical Site of Service: Clinical laboratory or outpatient facility

Data not available in the input.

Clinical & Coding Specifications

Clinical Context

A 28-year-old sexually active adult presents to a primary care clinic for routine preventive care and requests HIV screening. The clinician documents routine screening and sexual history that indicates no known HIV exposure but notes recent new sexual partners and inconsistent condom use. The clinical workflow begins with registration verifying insurance and consent for HIV testing, collection of demographic and risk information, and point-of-care or laboratory blood draw for the G0475 HIV antigen/antibody combination assay. The specimen is labeled, sent to the laboratory, and tested using a fourth-generation antigen/antibody platform. Negative results are reported to the patient by phone or portal; reactive or indeterminate results trigger reflex confirmatory testing per public health guidance and linkage to care workflows, including counseling and referral to infectious disease or HIV care. Typical site of service is an outpatient clinic, community health center, sexually transmitted infection clinic, or laboratory collection site. The typical patient scenario includes asymptomatic individuals presenting for routine screening, pregnant patients at initial prenatal visit or third-trimester rescreening, persons with potential occupational or non-occupational exposure, or patients presenting with symptoms suggestive of acute HIV infection who require combination antigen/antibody testing.

Coding Specifications

Modifier	Description	When to Use
`25`	Significant, separately identifiable evaluation and management service by the same physician on the same day of the procedure	Use when an E/M visit is performed the same day as `G0475` and is distinct from the testing visit (e.g., counseling, risk assessment).
`26`	Professional component	Use when billing only the professional component (interpretation) of the laboratory service, if applicable.
`TC`	Technical component	Use when billing only the technical component (laboratory processing) of the test.
`59`	Distinct procedural service	Use to indicate a distinct service when other services on the same day might be bundled with the test.
`90`	Reference (outside) laboratory	Use when the test was performed by an outside laboratory and only the referral is billed.
`52`	Reduced services	Use when the test was performed but at a reduced level of service compared with full procedure.
`53`	Discontinued procedure	Use if specimen collection or testing was started but discontinued for documented clinical reasons.
`76` Not applicable	Data not available in the input.
`QW`	CLIA-waived test	Use when the HIV combination assay is performed as a CLIA-waived point-of-care test and payer requires this modifier.
`GX` Not applicable	Data not available in the input.

Taxonomy Code	Specialty	Notes
`207Q00000X`	Family Medicine	Primary care clinicians ordering routine HIV screening and counseling.
`207R00000X`	Internal Medicine	Adult medicine clinicians performing screening and follow-up.
`208000000X`	Obstetrics & Gynecology	Prenatal screening and rescreening in pregnancy.
`208000000X` Duplicate	Data not available in the input.
`208000000Y` Not applicable	Data not available in the input.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`Z11.4`	Encounter for screening for human immunodeficiency virus [HIV]	Routine asymptomatic screening indication for `G0475`.
`O98.7`	Human immunodeficiency virus [HIV] disease complicating pregnancy, childbirth and the puerperium	Used for prenatal screening and management where `G0475` is performed in pregnancy.
`Z20.6`	Contact with and (suspected) exposure to HIV	Post-exposure screening indication where `G0475` is appropriate.
`R75`	Inconclusive laboratory evidence of human immunodeficiency virus [HIV]	Used when initial combination assay is reactive/indeterminate and follow-up testing is required.
`B20`	Human immunodeficiency virus [HIV] disease	Diagnosis for patients known to be HIV-positive where antigen/antibody testing may be part of monitoring or initial workup.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`36415`	Collection of venous blood by venipuncture	Performed immediately before `G0475` when laboratory-based `HIV antigen/antibody` testing requires venous specimen collection.
`87534`	Infectious agent antigen detection by immunoassay, HIV-1 antigen	May be used in laboratory workflows as a component or alternative assay in acute infection workup following a reactive `G0475`.
`87389`	Infectious agent antibody; HIV-1 and HIV-2, single result	Used when antibody-only testing is performed or as part of confirmatory assays following an initial `G0475` reactive result.
`87880`	Infectious agent detection by nucleic acid (e.g., HIV RNA), qualitative	Performed when `G0475` is reactive and nucleic acid testing (NAT) is required for confirmation or to detect acute infection.
`99401` Not applicable	Data not available in the input.

HCPCS G9490: Home Visit Assessment for Non-Homebound Patients

HCPCS-G0008-INFLUENZA-VACCINE-ADMINISTRATION

HCPCS G0008: Influenza Virus Vaccine Administration

HCPCS-G0009-PNEUMOCOCCAL-VACCINE-ADMINISTRATION

HCPCS G0009: Administration of Pneumococcal Vaccine

HCPCS-G0010-HEPATITIS-B-VACCINE-ADMINISTRATION

HCPCS G0010: Administration of Hepatitis B Vaccine

HCPCS-G0011-PREP-COUNSELING-HIV-RISK-REDUCTION-ADHERENCE

HCPCS G0011: Individual PrEP Counseling, HIV Risk Assessment

HCPCS-G0012-PRE-EXPOSURE-PROPHYLAXIS-INJECTION-HIV-PREVENTION

HCPCS G0012: Injection of Pre-Exposure Prophylaxis (PrEP) for HIV Prevention

HCPCS-G0013-PREP-INDIVIDUAL-COUNSELING-HIV-RISK-REDUCTION

HCPCS G0013: Individual PrEP Counseling and HIV Risk Assessment

HCPCS-G0017-PSYCHOTHERAPY-CRISIS-FIRST-60-MINUTES-NON-OFFICE

HCPCS G0017: Psychotherapy for Crisis, First 60 Minutes

HCPCS-G0018-PSYCHOTHERAPY-CRISIS-ADDITIONAL-30-MINUTES-NON-OFFICE

HCPCS G0018: Psychotherapy for Crisis, Additional 30 Minutes

HCPCS-G0019-COMMUNITY-HEALTH-INTEGRATION-SDOH-CARE-COORDINATION

HCPCS G0019: Community Health Integration for Social Determinants of Health

Showing 1–10 of 1996

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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Clinical & Coding Specifications

Clinical Context

Coding Specifications

Modifier	Description	When to Use
`25`	Significant, separately identifiable evaluation and management service by the same physician on the same day of the procedure	Use when an E/M visit is performed the same day as `G0475` and is distinct from the testing visit (e.g., counseling, risk assessment).
`26`	Professional component	Use when billing only the professional component (interpretation) of the laboratory service, if applicable.
`TC`	Technical component	Use when billing only the technical component (laboratory processing) of the test.
`59`	Distinct procedural service	Use to indicate a distinct service when other services on the same day might be bundled with the test.
`90`	Reference (outside) laboratory	Use when the test was performed by an outside laboratory and only the referral is billed.
`52`	Reduced services	Use when the test was performed but at a reduced level of service compared with full procedure.
`53`	Discontinued procedure	Use if specimen collection or testing was started but discontinued for documented clinical reasons.
`76` Not applicable	Data not available in the input.
`QW`	CLIA-waived test	Use when the HIV combination assay is performed as a CLIA-waived point-of-care test and payer requires this modifier.
`GX` Not applicable	Data not available in the input.

Taxonomy Code	Specialty	Notes
`207Q00000X`	Family Medicine	Primary care clinicians ordering routine HIV screening and counseling.
`207R00000X`	Internal Medicine	Adult medicine clinicians performing screening and follow-up.
`208000000X`	Obstetrics & Gynecology	Prenatal screening and rescreening in pregnancy.
`208000000X` Duplicate	Data not available in the input.
`208000000Y` Not applicable	Data not available in the input.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`Z11.4`	Encounter for screening for human immunodeficiency virus [HIV]	Routine asymptomatic screening indication for `G0475`.
`O98.7`	Human immunodeficiency virus [HIV] disease complicating pregnancy, childbirth and the puerperium	Used for prenatal screening and management where `G0475` is performed in pregnancy.
`Z20.6`	Contact with and (suspected) exposure to HIV	Post-exposure screening indication where `G0475` is appropriate.
`R75`	Inconclusive laboratory evidence of human immunodeficiency virus [HIV]	Used when initial combination assay is reactive/indeterminate and follow-up testing is required.
`B20`	Human immunodeficiency virus [HIV] disease	Diagnosis for patients known to be HIV-positive where antigen/antibody testing may be part of monitoring or initial workup.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`36415`	Collection of venous blood by venipuncture	Performed immediately before `G0475` when laboratory-based `HIV antigen/antibody` testing requires venous specimen collection.
`87534`	Infectious agent antigen detection by immunoassay, HIV-1 antigen	May be used in laboratory workflows as a component or alternative assay in acute infection workup following a reactive `G0475`.
`87389`	Infectious agent antibody; HIV-1 and HIV-2, single result	Used when antibody-only testing is performed or as part of confirmatory assays following an initial `G0475` reactive result.
`87880`	Infectious agent detection by nucleic acid (e.g., HIV RNA), qualitative	Performed when `G0475` is reactive and nucleic acid testing (NAT) is required for confirmation or to detect acute infection.
`99401` Not applicable	Data not available in the input.

HCPCS G9490: Home Visit Assessment for Non-Homebound Patients

HCPCS-G0008-INFLUENZA-VACCINE-ADMINISTRATION

HCPCS G0008: Influenza Virus Vaccine Administration

HCPCS-G0009-PNEUMOCOCCAL-VACCINE-ADMINISTRATION

HCPCS G0009: Administration of Pneumococcal Vaccine

HCPCS-G0010-HEPATITIS-B-VACCINE-ADMINISTRATION

HCPCS G0010: Administration of Hepatitis B Vaccine

HCPCS-G0011-PREP-COUNSELING-HIV-RISK-REDUCTION-ADHERENCE

HCPCS G0011: Individual PrEP Counseling, HIV Risk Assessment

HCPCS-G0012-PRE-EXPOSURE-PROPHYLAXIS-INJECTION-HIV-PREVENTION

HCPCS G0012: Injection of Pre-Exposure Prophylaxis (PrEP) for HIV Prevention

HCPCS-G0013-PREP-INDIVIDUAL-COUNSELING-HIV-RISK-REDUCTION

HCPCS G0013: Individual PrEP Counseling and HIV Risk Assessment

HCPCS-G0017-PSYCHOTHERAPY-CRISIS-FIRST-60-MINUTES-NON-OFFICE

HCPCS G0017: Psychotherapy for Crisis, First 60 Minutes

HCPCS-G0018-PSYCHOTHERAPY-CRISIS-ADDITIONAL-30-MINUTES-NON-OFFICE

HCPCS G0018: Psychotherapy for Crisis, Additional 30 Minutes

HCPCS-G0019-COMMUNITY-HEALTH-INTEGRATION-SDOH-CARE-COORDINATION

HCPCS G0019: Community Health Integration for Social Determinants of Health

Showing 1–10 of 1996

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.

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HCPCS G0475: HIV Antigen/Antibody Combination Assay, Screening

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Billing Code Overview

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HCPCS G0475: HIV Antigen/Antibody Combination Assay, Screening

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Billing Code Overview

Clinical & Coding Specifications

Clinical Context

Coding Specifications

Related Diagnoses

Related CPT Codes

Related Codes

References

Clinical & Coding Specifications

Clinical Context

Coding Specifications

Related Diagnoses

Related CPT Codes

Related Codes

References

HCPCS G0475: HIV Antigen/Antibody Combination Assay, Screening

Sign up for hcpcs G0475 policy alerts

Billing Code Overview

HCPCS G0475: HIV Antigen/Antibody Combination Assay, Screening

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Billing Code Overview

Clinical & Coding Specifications

Clinical Context

Coding Specifications

Related Diagnoses

Related CPT Codes

Related Codes

What does HCPCS code G0475 represent and where is it typically performed?

Which billing modifiers are relevant for G0475 and when are they used?

What related CPT or lab codes should be considered with G0475 in the testing workflow?

For which clinical indications is G0475 typically used?

Which payers are included in the coverage analysis for G0475 and are reimbursement rates provided?

References

Clinical & Coding Specifications

Clinical Context

Coding Specifications

Related Diagnoses

Related CPT Codes

Related Codes

What does HCPCS code G0475 represent and where is it typically performed?

Which billing modifiers are relevant for G0475 and when are they used?

What related CPT or lab codes should be considered with G0475 in the testing workflow?

For which clinical indications is G0475 typically used?

Which payers are included in the coverage analysis for G0475 and are reimbursement rates provided?

References