HCPCS Q5146: Trastuzumab-strf (Hercessi) Injection, 10 mg

HCPCS Level II code Q5146 designates the biosimilar injection of trastuzumab-strf (Hercessi), supplied in a 10 mg unit. As a biosimilar to trastuzumab, this product is used in the management of HER2-positive malignancies and is billed under HCPCS Level II for drug administration and inventory reporting. Nationally, accurate coding for biosimilar oncologic agents affects claims processing, payer policy application, and aggregation of utilization data across outpatient infusion settings.

Key payers discussed include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. The publication provides readers with benchmarking context, common payer coverage considerations, and clinical setting implications relevant to billing and reimbursement for biosimilar trastuzumab products.

Readers will learn how HCPCS Level II code Q5146 is used to represent a 10 mg injectable unit of trastuzumab-strf (Hercessi), the typical sites of service where it is administered, and which national payers are commonly involved in coverage decisions. The summary also outlines the types of benchmarks and policy updates covered in the full publication, plus clinical context for use of biosimilar trastuzumab in HER2-positive cancer care. Data not available in the input for associated taxonomies, ICD-10 diagnoses, and related service-line specifics are noted where applicable.

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Billing Code Overview

HCPCS Level II code Q5146 represents an injection formulation of trastuzumab-strf (Hercessi), biosimilar, 10 mg. This code denotes a biologic oncology medication administered via injection for indications consistent with trastuzumab therapy, typically targeting HER2-positive cancers.

Service Type: Injection, biosimilar monoclonal antibody therapy

Typical Site of Service: Outpatient infusion center or hospital outpatient department

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HCPCS Q5146: Trastuzumab-strf (Hercessi) Injection, 10 mg

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Sign up for hcpcs Q5146 policy alerts

Get alerted when payer policies referencing Q5146 are released or updated.

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Receive email alerts as soon as relevant payer policies are published or updated.

Billing Code Overview

Service Type: Injection, biosimilar monoclonal antibody therapy

Typical Site of Service: Outpatient infusion center or hospital outpatient department

Clinical & Coding Specifications

Clinical Context

A typical patient is an adult with HER2-positive breast cancer receiving intravenous biosimilar trastuzumab therapy in an outpatient infusion center or hospital outpatient department. A common scenario: a patient with early-stage HER2-positive invasive ductal carcinoma receives an initial loading dose followed by maintenance dosing every 3 weeks (or weekly per protocol) administered by an oncology infusion nurse under the supervision of a medical oncologist. Pre-infusion assessment includes vital signs, review of cardiac history and recent left ventricular ejection fraction (LVEF) assessment, verification of therapy orders, and review for hypersensitivity risk. The pharmacy prepares Q5146 as a 10 mg vial of trastuzumab‑strf (Hercessi) biosimilar; dosing is calculated by body weight (mg/kg) or fixed protocol, documented in the medical record, and the administered volume and vial usage are recorded for billing, including any wastage handled per payor policies. Infusion-related monitoring includes observation for infusion reactions, cardiac monitoring when indicated, and documentation of adverse events and concurrent chemotherapy agents. Typical sites of service are outpatient infusion centers, physician offices with infusion capability, and hospital outpatient departments.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`C50.911`	Malignant neoplasm of unspecified site of right female breast	Common primary diagnosis for HER2-positive breast cancer patients receiving trastuzumab biosimilar therapy.
`C50.912`	Malignant neoplasm of unspecified site of left female breast	As above for left-sided breast cancer treated with HER2-targeted therapy.
`C50.919`	Malignant neoplasm of unspecified site of breast, unspecified	Used when laterality is unspecified and trastuzumab is part of systemic therapy.
`C79.81`	Malignant neoplasm of bone	Indicates metastatic disease where trastuzumab may be part of systemic therapy for HER2-positive metastatic breast cancer.
`C78.7`	Secondary malignant neoplasm of liver and intrahepatic bile duct	Relevant for metastatic spread requiring systemic HER2-targeted therapy.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`96413`	Chemotherapy administration, intravenous infusion technique; up to 1 hour, single or initial substance/drug	Used for billing the infusion administration time when trastuzumab biosimilar is infused as the single/initial agent during an outpatient visit.
`96415`	Chemotherapy administration, IV infusion; each additional hour	Billed when the infusion duration exceeds the time covered by the primary infusion code and additional hours are required.
`96401`	Chemotherapy administration, injection, subcutaneous or intramuscular; non-hormonal antineoplastic	May be used for bolus injectable agents when applicable; not typical for trastuzumab which is IV.
`36415`	Collection of venous blood by venipuncture	Billed for pre-infusion labs such as complete blood count or BMP drawn prior to infusion.
`93000`	Electrocardiogram, routine ECG with at least 12 leads; with interpretation and report	Used when cardiac monitoring or baseline ECG is required in patients with cardiac risk prior to trastuzumab administration.

Related Modifiers

8 rows

Modifier	Description	When to Use
62	Modifier 62 indicates that two surgeons function as co‑surgeons, each performing distinct parts of the same primary surgical procedure. It is appended to the primary procedure code (and any…	- Use modifier -62 when two surgeons act as co‑surgeons (both primary surgeons) on a single definitive primary procedure, each performing distinct parts of the same surgical procedure (append -62 to…
78	CPT modifier -78 indicates an unplanned, related return to the operating or procedure room by the same provider during the global postoperative period. It is appended when treatment for a…	- Use modifier -78 when an unplanned, related complication during the original procedure’s global postoperative period requires the patient to return to a formal operating or procedure room and the…
80	CPT® Modifier 80 (Assistant Surgeon) is appended to a surgical CPT code when a physician (MD or DO) provides full, continuous assistance throughout the operative procedure. It is intended only for…	- Use CPT Modifier -80 when a physician (MD or DO) serves as an assistant surgeon and provides full, continuous assistance throughout the entire operative procedure; append -80 to the surgical CPT…
23	Modifier -23 (Unusual Anesthesia) is used on anesthesia service CPT codes when a procedure that normally requires no anesthesia or only local anesthesia must be performed under general anesthesia…	- Use modifier -23 only on anesthesia CPT codes (00100–01999) when a procedure that normally requires no anesthesia or only local anesthesia must be performed under general anesthesia because of…
52	Modifier ‑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…
53	Modifier 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…
22	Modifier –22 (Increased Procedural Services) is used when a reported procedure is substantially more extensive than normally required. The CPT Manual and CMS state it may be appended only when the…	- When to use: Append modifier -22 to a procedural CPT code when the service performed is substantially more extensive than the usual service described by that code — i.e., the procedure required…
55	Modifier –55 indicates the billing provider furnished only postoperative management for a procedure that has a global surgical period. According to AAPC, this modifier is appended to the same CPT…	- Use modifier -55 when billing the same CPT surgical code that has a 10- or 90-day global period and you, as a provider other than the original surgeon, furnished ONLY postoperative management (no…

Related Provider Taxonomies

8 rows

Taxonomy Code	Specialty	Notes
207RC0000X	Cardiovascular Disease Physician	An internist who specializes in diseases of the heart and blood vessels and manages complex cardiac conditions such as heart attacks and life-threaten…
207RP1001X	Pulmonary Disease Physician	An internist who treats diseases of the lungs and airways. The pulmonologist diagnoses and treats cancer, pneumonia, pleurisy, asthma, occupational an…
363L00000X	Nurse Practitioner	(1) A registered nurse provider with a graduate degree in nursing prepared for advanced practice involving independent and interdependent decision mak…
2084P0804X	Child & Adolescent Psychiatry Physician	Child & Adolescent Psychiatry is a subspecialty of psychiatry with additional skills and training in the diagnosis and treatment of developmental, beh…
174V00000X	Clinical Ethicist	A clinical ethicist has been trained in bioethics and ethics case consultation. The clinical ethicist addresses medical-ethical dilemmas arising in c…
1835P1200X	Pharmacotherapy Pharmacist	A licensed pharmacist who has demonstrated specialized knowledge and skill in optimizing pharmacotherapeutic care of patients, by developing, implemen…
163WG0000X	General Practice Registered Nurse	Nursing Service Providers · Registered Nurse
2471M1202X	Magnetic Resonance Imaging Radiologic Technologist	A radiologic technologist who specializes in magnetic resonance imaging (MRI) and is appropriately educated and trained, consistent with nationally re…

HCPCS Level II Q4139: Injectable Amniomatrix or Biodmatrix, 1 cc

HCPCS-LEVEL-II-Q4256-AREA-BASED-PROCEDURAL-ADD-ON-PER-SQ-CM

HCPCS Level II Q4256: Area-Based Procedural Add-On, Per sq cm

HCPCS-LEVEL-II-Q5132-ADALIMUMAB-AFZB-ABRILADA-10MG-INJECTION

HCPCS Level II Q5132: Adalimumab-afzb (Abrilada) 10 mg Injection

HCPCS-Q0035-CARDIOKYMOGRAPHY-CARDIAC-MOTION-RECORDING

HCPCS Q0035: Cardiokymography, Cardiac Motion Recording

HCPCS-Q0081-INFUSION-THERAPY-NON-CHEMOTHERAPEUTIC-PER-VISIT

HCPCS Q0081: Infusion Therapy, Non-Chemotherapeutic, Per Visit

HCPCS-Q0083-CHEMOTHERAPY-NON-INFUSION-ADMINISTRATION

HCPCS Q0083: Chemotherapy Administration, Non-Infusion

HCPCS-Q0084-CHEMOTHERAPY-INFUSION-ADMINISTRATION-PER-VISIT

HCPCS Q0084: Chemotherapy Infusion Administration, Per Visit

HCPCS-Q0085-CHEMOTHERAPY-INFUSION-PLUS-OTHER-TECHNIQUES-PER-VISIT

HCPCS Q0085: Chemotherapy Administration, Infusion Plus Other Technique(s) per Visit

HCPCS-Q0091-PAP-SMEAR-SPECIMEN-COLLECTION-TRANSPORT

HCPCS Q0091: Screening Pap Smear Specimen Collection and Transport

HCPCS-Q0092-PORTABLE-XRAY-EQUIPMENT-SETUP

HCPCS Q0092: Set-up of Portable X-Ray Equipment

Showing 1–10 of 629

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

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`C50.911`	Malignant neoplasm of unspecified site of right female breast	Common primary diagnosis for HER2-positive breast cancer patients receiving trastuzumab biosimilar therapy.
`C50.912`	Malignant neoplasm of unspecified site of left female breast	As above for left-sided breast cancer treated with HER2-targeted therapy.
`C50.919`	Malignant neoplasm of unspecified site of breast, unspecified	Used when laterality is unspecified and trastuzumab is part of systemic therapy.
`C79.81`	Malignant neoplasm of bone	Indicates metastatic disease where trastuzumab may be part of systemic therapy for HER2-positive metastatic breast cancer.
`C78.7`	Secondary malignant neoplasm of liver and intrahepatic bile duct	Relevant for metastatic spread requiring systemic HER2-targeted therapy.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`96413`	Chemotherapy administration, intravenous infusion technique; up to 1 hour, single or initial substance/drug	Used for billing the infusion administration time when trastuzumab biosimilar is infused as the single/initial agent during an outpatient visit.
`96415`	Chemotherapy administration, IV infusion; each additional hour	Billed when the infusion duration exceeds the time covered by the primary infusion code and additional hours are required.
`96401`	Chemotherapy administration, injection, subcutaneous or intramuscular; non-hormonal antineoplastic	May be used for bolus injectable agents when applicable; not typical for trastuzumab which is IV.
`36415`	Collection of venous blood by venipuncture	Billed for pre-infusion labs such as complete blood count or BMP drawn prior to infusion.
`93000`	Electrocardiogram, routine ECG with at least 12 leads; with interpretation and report	Used when cardiac monitoring or baseline ECG is required in patients with cardiac risk prior to trastuzumab administration.

Related Modifiers

8 rows

Modifier	Description	When to Use
62	Modifier 62 indicates that two surgeons function as co‑surgeons, each performing distinct parts of the same primary surgical procedure. It is appended to the primary procedure code (and any…	- Use modifier -62 when two surgeons act as co‑surgeons (both primary surgeons) on a single definitive primary procedure, each performing distinct parts of the same surgical procedure (append -62 to…
78	CPT modifier -78 indicates an unplanned, related return to the operating or procedure room by the same provider during the global postoperative period. It is appended when treatment for a…	- Use modifier -78 when an unplanned, related complication during the original procedure’s global postoperative period requires the patient to return to a formal operating or procedure room and the…
80	CPT® Modifier 80 (Assistant Surgeon) is appended to a surgical CPT code when a physician (MD or DO) provides full, continuous assistance throughout the operative procedure. It is intended only for…	- Use CPT Modifier -80 when a physician (MD or DO) serves as an assistant surgeon and provides full, continuous assistance throughout the entire operative procedure; append -80 to the surgical CPT…
23	Modifier -23 (Unusual Anesthesia) is used on anesthesia service CPT codes when a procedure that normally requires no anesthesia or only local anesthesia must be performed under general anesthesia…	- Use modifier -23 only on anesthesia CPT codes (00100–01999) when a procedure that normally requires no anesthesia or only local anesthesia must be performed under general anesthesia because of…
52	Modifier ‑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…
53	Modifier 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…
22	Modifier –22 (Increased Procedural Services) is used when a reported procedure is substantially more extensive than normally required. The CPT Manual and CMS state it may be appended only when the…	- When to use: Append modifier -22 to a procedural CPT code when the service performed is substantially more extensive than the usual service described by that code — i.e., the procedure required…
55	Modifier –55 indicates the billing provider furnished only postoperative management for a procedure that has a global surgical period. According to AAPC, this modifier is appended to the same CPT…	- Use modifier -55 when billing the same CPT surgical code that has a 10- or 90-day global period and you, as a provider other than the original surgeon, furnished ONLY postoperative management (no…

Related Provider Taxonomies

8 rows

Taxonomy Code	Specialty	Notes
207RC0000X	Cardiovascular Disease Physician	An internist who specializes in diseases of the heart and blood vessels and manages complex cardiac conditions such as heart attacks and life-threaten…
207RP1001X	Pulmonary Disease Physician	An internist who treats diseases of the lungs and airways. The pulmonologist diagnoses and treats cancer, pneumonia, pleurisy, asthma, occupational an…
363L00000X	Nurse Practitioner	(1) A registered nurse provider with a graduate degree in nursing prepared for advanced practice involving independent and interdependent decision mak…
2084P0804X	Child & Adolescent Psychiatry Physician	Child & Adolescent Psychiatry is a subspecialty of psychiatry with additional skills and training in the diagnosis and treatment of developmental, beh…
174V00000X	Clinical Ethicist	A clinical ethicist has been trained in bioethics and ethics case consultation. The clinical ethicist addresses medical-ethical dilemmas arising in c…
1835P1200X	Pharmacotherapy Pharmacist	A licensed pharmacist who has demonstrated specialized knowledge and skill in optimizing pharmacotherapeutic care of patients, by developing, implemen…
163WG0000X	General Practice Registered Nurse	Nursing Service Providers · Registered Nurse
2471M1202X	Magnetic Resonance Imaging Radiologic Technologist	A radiologic technologist who specializes in magnetic resonance imaging (MRI) and is appropriately educated and trained, consistent with nationally re…

HCPCS Level II Q4139: Injectable Amniomatrix or Biodmatrix, 1 cc

HCPCS-LEVEL-II-Q4256-AREA-BASED-PROCEDURAL-ADD-ON-PER-SQ-CM

HCPCS Level II Q4256: Area-Based Procedural Add-On, Per sq cm

HCPCS-LEVEL-II-Q5132-ADALIMUMAB-AFZB-ABRILADA-10MG-INJECTION

HCPCS Level II Q5132: Adalimumab-afzb (Abrilada) 10 mg Injection

HCPCS-Q0035-CARDIOKYMOGRAPHY-CARDIAC-MOTION-RECORDING

HCPCS Q0035: Cardiokymography, Cardiac Motion Recording

HCPCS-Q0081-INFUSION-THERAPY-NON-CHEMOTHERAPEUTIC-PER-VISIT

HCPCS Q0081: Infusion Therapy, Non-Chemotherapeutic, Per Visit

HCPCS-Q0083-CHEMOTHERAPY-NON-INFUSION-ADMINISTRATION

HCPCS Q0083: Chemotherapy Administration, Non-Infusion

HCPCS-Q0084-CHEMOTHERAPY-INFUSION-ADMINISTRATION-PER-VISIT

HCPCS Q0084: Chemotherapy Infusion Administration, Per Visit

HCPCS-Q0085-CHEMOTHERAPY-INFUSION-PLUS-OTHER-TECHNIQUES-PER-VISIT

HCPCS Q0085: Chemotherapy Administration, Infusion Plus Other Technique(s) per Visit

HCPCS-Q0091-PAP-SMEAR-SPECIMEN-COLLECTION-TRANSPORT

HCPCS Q0091: Screening Pap Smear Specimen Collection and Transport

HCPCS-Q0092-PORTABLE-XRAY-EQUIPMENT-SETUP

HCPCS Q0092: Set-up of Portable X-Ray Equipment

Showing 1–10 of 629

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

HCPCS Q5146: Trastuzumab-strf (Hercessi) Injection, 10 mg

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Billing Code Overview

OpenPayer

HCPCS Q5146: Trastuzumab-strf (Hercessi) Injection, 10 mg

Sign up for hcpcs Q5146 policy alerts

Billing Code Overview

Clinical & Coding Specifications

Clinical Context

Related Diagnoses

Related CPT Codes

Related Modifiers

Related Provider Taxonomies

Related Codes

References

Clinical & Coding Specifications

Clinical Context

Related Diagnoses

Related CPT Codes

Related Modifiers

Related Provider Taxonomies

Related Codes

References

HCPCS Q5146: Trastuzumab-strf (Hercessi) Injection, 10 mg

Sign up for hcpcs Q5146 policy alerts

Billing Code Overview

HCPCS Q5146: Trastuzumab-strf (Hercessi) Injection, 10 mg

Sign up for hcpcs Q5146 policy alerts

Billing Code Overview

Clinical & Coding Specifications

Clinical Context

Related Diagnoses

Related CPT Codes

Related Modifiers

Related Provider Taxonomies

Related Codes

What does HCPCS code Q5146 represent and where is it typically used?

What is the typical clinical scenario for administration of trastuzumab‑strf (Hercessi) billed with Q5146?

Which modifiers are relevant when billing Q5146 and what do they signify?

What procedure codes are commonly billed alongside Q5146 for infusion administration and monitoring?

Which ICD-10 diagnosis codes are associated with billing Q5146?

References

Clinical & Coding Specifications

Clinical Context

Related Diagnoses

Related CPT Codes

Related Modifiers

Related Provider Taxonomies

Related Codes

What does HCPCS code Q5146 represent and where is it typically used?

What is the typical clinical scenario for administration of trastuzumab‑strf (Hercessi) billed with Q5146?

Which modifiers are relevant when billing Q5146 and what do they signify?

What procedure codes are commonly billed alongside Q5146 for infusion administration and monitoring?

Which ICD-10 diagnosis codes are associated with billing Q5146?

References