Summary & Overview

HCPCS G8602: IV Thrombolytic Not Initiated Within 4.5 Hours of Last Known Well

HCPCS Level II code G8602 denotes cases in which intravenous thrombolytic therapy for acute ischemic stroke was not initiated within 4.5 hours (≤ 270 minutes) of the patient's time last known well and no reason is documented. This code functions as a clinical timing and quality-reporting marker that matters for national stroke care tracking, performance measurement, and administrative reporting.

Key payers included in this analysis are Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of the code's clinical context, common sites of service (emergency department and inpatient acute care), and the role of the code in documenting missed therapeutic windows for IV thrombolysis. The publication summarizes typical use cases and reporting implications, highlights where benchmarking and quality metrics intersect with billing, and outlines what information is available versus missing in the input (for example, associated ICD-10 diagnoses and detailed payer policy variations).

This national-level summary is intended for clinicians, coding professionals, and policy analysts seeking clear guidance on the purpose and practical significance of G8602, how it relates to acute stroke care timing, and what to expect in payer and quality reporting contexts.

AetnaBlue Cross Blue ShieldCigna HealthUnitedHealthcareMedicareG8602HCPCS Level IIstrokethrombolytic therapytime-to-treatmentemergency departmentquality reportingacute care

Billing Code Overview

HCPCS Level II code G8602 indicates IV thrombolytic therapy not initiated within 4.5 hours (≤ 270 minutes) of time last known well, reason not given. The service type reflected is acute stroke thrombolysis reporting / stroke treatment timing. The typical site of service for events captured by this code is the hospital setting, most commonly emergency departments and inpatient acute care units where evaluation and potential administration of intravenous thrombolytics for ischemic stroke occur.

Data not available in the input.

Clinical & Coding Specifications

Clinical Context

A typical patient is an adult who presents to the emergency department with acute onset focal neurologic deficits suspicious for ischemic stroke. The patient arrived to an emergency department or comprehensive stroke center at 5 hours after the time last known well. On initial evaluation the stroke team performed an urgent neurologic exam, non-contrast head CT to exclude hemorrhage, and CT angiography/perfusion or MRI as indicated. Intravenous thrombolytic therapy (alteplase) was considered but was not initiated because the patient arrived outside the FDA-recommended therapeutic window of 4.5 hours (270 minutes) from time last known well. The clinical workflow documents time last known well, arrival time, imaging results, reasons for not administering IV thrombolytic therapy, informed consent discussion when applicable, and disposition (admission to stroke unit, transfer for endovascular therapy if large vessel occlusion and within an extended window). The billing code G8602 is used to indicate IV thrombolytic therapy was not initiated within 4.5 hours of last known well and the chart does not document a reason for the delay or contraindication.

Coding Specifications

Modifier	Description	When to Use
`22`	Increased procedural services	Use when documentation supports substantially greater physician work for stroke evaluation or complicated informed consent not typical for the ED visit.
`23`	Unusual anesthesia	Use when general anesthesia is required for an associated procedure (e.g., emergent endovascular intervention) though not typical for IV thrombolytic decision.
`52`	Reduced services	Use when evaluation or services were partially reduced compared to the usual service due to clinical limitations.
`53`	Discontinued procedure	Use when thrombolytic therapy was initiated but stopped before completion for documented reasons (not typical for `G8602`).
`54`	Surgical care only	Use when another provider performs only the surgical portion of care; rarely applicable to IV thrombolysis documentation.
`55`	Postoperative management only	Use when the billing provider performs only post-procedure inpatient management after an intervention.
`56`	Preoperative management only	Use when provider performed only pre-procedure evaluation; applicable if decision-making about thrombolysis occurred before transfer.
`62`	Two surgeons	Use when two surgeons are required for an operative procedure associated with stroke care (rarely used for IV thrombolysis).
`AS`	Physician assistant, nurse practitioner, or clinical nurse specialist services with surgical package	Use when advanced practice providers bill under their own NPI for elements of the surgical package related to stroke care.
`CO`	Out-of-network	Use when provider is out-of-network for the patient’s insurer and this affects billing.
`CQ`	Service performed in part by a resident, no teaching physician participation	Use when service is provided by a resident without attending involvement and billing rules permit.
`QK`	Medical direction of two or more qualified individuals	Use when the physician medically directs multiple qualified individuals who participate in care.
`QX`	CRNA service with medical direction by a physician	Use when CRNA provides anesthesia under physician medical direction during a related procedure.
`QY`	Medical direction of one CRNA by a physician	Use when physician directs a single CRNA for an associated anesthetic.

Taxonomy Code	Specialty	Notes
`2084P0800X`	Neurology	Stroke neurologists direct acute stroke evaluation and decision-making about thrombolysis.
`2080N0402X`	Emergency Medicine	Emergency physicians perform initial evaluation, imaging triage, and time-sensitive decisions.
`2086S0105X`	Vascular Neurology	Specialists in cerebrovascular disease provide directed stroke care and advanced decision-making.
`207P00000X`	Internal Medicine	Hospitalists or internal medicine physicians manage inpatient post-stroke care and documentation.
`2083N0402X`	Interventional Neuroradiology	Interventionalists evaluate and perform endovascular thrombectomy when indicated; interact with thrombolysis decisions.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`I63.9`	Cerebral infarction, unspecified	Common primary diagnosis for ischemic stroke when specific territory or etiology is not yet determined; directly related to thrombolytic consideration.
`I63.3`	Cerebral infarction due to thrombosis of cerebral arteries	Represents ischemic stroke subtype where IV thrombolysis may be considered if within time window.
`I63.4`	Cerebral infarction due to embolism of cerebral arteries	Embolic strokes are a common indication for urgent reperfusion therapy evaluation.
`I61.9`	Intracerebral hemorrhage, unspecified	Must be excluded by imaging prior to thrombolytic therapy; a documented hemorrhage is a contraindication.
`G45.9`	Transient cerebral ischemic attack, unspecified	TIA may present similarly but typically does not qualify for IV thrombolysis; relevant to differential diagnosis.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`70450`	Computed tomography, head or brain; without contrast material	Initial non-contrast head CT to exclude intracranial hemorrhage prior to consideration of IV thrombolysis.
`74177`	CT angiography, abdomen and pelvis; with contrast material, including non-contrast images, if performed (placeholder for vascular imaging)	In many stroke workflows, CT angiography of the head/neck is performed to evaluate large vessel occlusion; billing code adjusted to site-specific CTA codes when used.
`70553`	Magnetic resonance imaging, brain, without and with contrast material, multiple sequences	MRI brain including diffusion-weighted imaging to confirm acute ischemia when available and appropriate.
`96372`	Therapeutic, prophylactic, or diagnostic injection; subcutaneous or intramuscular (per injection)	Represents administration of IV medications; sometimes used for documentation of bolus medication administration associated with thrombolytic protocols (site-dependent).
`92950`	Cardiopulmonary resuscitation (CPR), manual	CPT used if resuscitation is required during acute stroke evaluation or treatment; included as an adjacent emergent intervention.

Note: If specific site CPT codes differ (for example, head and neck CTA codes), substitute the institutionally appropriate CPT for vascular imaging. The billing code G8602 documents that IV thrombolytic therapy was not initiated within 4.5 hours and is used in the patient's administrative reporting; the CPT codes above represent imaging and procedures commonly performed before or after the thrombolysis decision.