CPT Codes for Transthoracic Echocardiography Billing

The primary CPT code for a transthoracic echocardiogram is 93306, which covers a complete TTE with 2D imaging, M-mode, spectral Doppler, and color flow Doppler. 

Transthoracic echocardiography is a noninvasive cardiac ultrasound technique used to evaluate ventricular function, valvular disease, chamber size, heart failure, and cardiomyopathies — and the CPT code selected on each claim determines reimbursement, Doppler billing rules, and audit exposure. 

The American Medical Association maintains the CPT code set, and CMS ties each TTE code to specific documentation and medical necessity requirements.

Below, this guide covers

• 93306, 93307, 93308, and congenital echo codes
• Add-on Doppler codes and when they can and cannot be billed separately
• Modifier 26 vs TC and professional/technical billing
• Documentation requirements that prevent denials
• Medicare coverage rules and real-world coding pitfalls

What are the core TTE CPT codes?

The following CPT codes form the standard transthoracic echocardiography billing family. Each one corresponds to a different scope of study and Doppler inclusion.

CPT code	Description	Doppler included	Study scope
93306	Complete TTE with spectral Doppler and color flow Doppler	Yes (bundled)	Comprehensive adult
93307	Complete TTE without spectral or color Doppler	No	Complete imaging only
93308	Follow-up or limited TTE	No	Focused or repeat
93303	TTE for congenital cardiac anomalies, complete	No (add-ons allowed)	Congenital studies
93304	TTE for congenital cardiac anomalies, follow-up or limited	No (add-ons allowed)	Limited congenital

CPT 93306

CPT 93306 is the most commonly billed echocardiography code in outpatient cardiology. The official AMA description reads “Echocardiography, transthoracic, real-time with image documentation (2D), includes M-mode recording, when performed, complete, with spectral Doppler echocardiography, and with color flow Doppler echocardiography.”

Because 93306 bundles both spectral and color flow Doppler into the base code, separately billing +93320 or +93325 alongside 93306 is generally inappropriate and a frequent NCCI edit trigger. 

The bundled structure means 93306 is an all-in-one code — the complete echocardiogram transthoracic with color flow that most cardiology practices bill daily.

CPT 93307

CPT 93307 covers a complete transthoracic echocardiogram without Doppler. 

All required cardiac structures must still be evaluated (the study is complete in scope), but no spectral or color flow Doppler analysis is performed or documented. 

When a practice performs 93307 and also performs Doppler studies during the same encounter, the add-on codes +93320 and +93325 become separately billable.

CPT 93308

CPT 93308 applies to follow-up or limited TTE studies where a focused evaluation (rather than a full cardiac assessment) is clinically appropriate. 

Repeat studies for known conditions, targeted valve reassessments, and post-procedure checks typically fall under 93308. Billing 93306 for a limited study is a common audit flag because the documentation won’t support a complete examination.

CPT 93303 and 93304

CPT 93303 and 93304 are specifically designated for congenital cardiac anomalies — not simply “echocardiography without Doppler” as some coding resources incorrectly describe. 

CPT 93303 covers a complete congenital TTE, while 93304 covers a follow-up or limited congenital study. Unlike 93306, congenital echo codes allow separate billing of Doppler add-ons (+93320 and +93325) because Doppler is not bundled into the base code.

Pediatric cardiology practices and adult congenital heart programs should verify that coders assign 93303/93304 (not 93306/93307) when the clinical indication is a congenital anomaly, since the documentation requirements and add-on billing rules differ.

Which add-on codes can be billed with TTE?

Add-on codes supplement the base TTE code when specific modalities are performed and documented. The billing rules depend entirely on which base code appears on the claim.

A critical nuance that trips up many cardiology coders — +93320 and +93321 should not appear on the same claim. EviCore’s 2025 cardiac imaging guideline explicitly states these two codes should not be requested or billed together, since 93321 is the limited version of 93320.

How do modifier 26 and modifier TC work for echocardiography?

Echocardiography reimbursement splits into two components, and the modifier determines who gets paid for what.

Modifier	Component	Who bills	Typical scenario
26	Professional (interpretation and report)	Interpreting physician	Cardiologist reads images at a hospital
TC	Technical (equipment, sonographer, supplies)	Facility or practice owning equipment	Hospital or imaging center performs the scan
No modifier	Global (both components)	Provider performing and interpreting	Physician-owned office doing everything

For practices where the cardiologist owns the equipment and interprets the study, global billing (no modifier) captures both components. 

When a hospital employs the sonographer and owns the equipment but a separate cardiologist interprets, the hospital bills TC and the cardiologist bills modifier 26.

The reimbursement split is significant — the professional component typically represents about 25–35% of the total allowed amount, while the technical component captures the rest. Practices that misapply modifiers (or forget them entirely) risk duplicate billing flags and payer recoupments.

What documentation does 93306 require?

CMS and payer policies require that a complete 93306 study include documented evaluation of specific cardiac structures. Missing even one required element can downcode the claim to 93308 or trigger a denial.

A compliant 93306 report should document evaluation of

• Aortic root
• Pericardium
• Left and right atria
• Color flow Doppler findings
• Mitral, tricuspid, and aortic valves
• Spectral Doppler findings (pulsed wave and/or continuous wave)
• Left and right ventricles (including wall motion and ejection fraction)

The interpretation and report must be completed by the interpreting physician and signed. When CMS billing guidance for TTE references medical necessity, the ICD-10 diagnosis code on the claim must justify the complete study — CMS lists over 1,000 eligible diagnostic indications.

If spectral Doppler or color flow Doppler documentation is absent from the report, the study no longer meets the 93306 definition. The correct code drops to 93307 (complete without Doppler) or 93308 (limited), and billing 93306 anyway becomes a compliance risk.

What causes echocardiography claim denials?

Most echo billing denials fall into predictable patterns (and the frustrating part is that nearly all of them are preventable with proper claim-level checks).

Medicare does not impose a hard annual limit on echocardiography frequency, but repeat studies face scrutiny from Medicare Administrative Contractors (MACs). 

Each repeat TTE needs documentation of a new clinical indication or meaningful change in the patient’s condition — performing serial echos on a stable patient without clinical justification invites post-payment review.

How does Medicare cover echocardiography?

Medicare Part B covers medically necessary echocardiography (both TTE and TEE) and generally pays 80% of the approved amount after the annual deductible. 

The patient owes the remaining 20% coinsurance, and facility-based studies may carry additional charges depending on the site of service.

Common Medicare-covered indications include

• Cardiomyopathy evaluation
• Pre-operative cardiac risk assessment
• Evaluation of heart murmurs or suspected valvular disease
• Heart failure assessment (dyspnea, fatigue, reduced ejection fraction)
• Monitoring after cardiac surgery or intervention
• Congenital heart disease diagnosis

Proper ICD-10 coding is the linchpin of Medicare coverage — the diagnosis must clinically justify why the echo was ordered. A claim with CPT 93306 and a vague or unsupported ICD-10 code will stall in adjudication regardless of how well the echo itself was documented.

Accurate echo billing starts with the right billing partner

Echocardiography coding sits at the intersection of clinical documentation, Doppler modality rules, modifier logic, and payer-specific edits — and the margin for error is thin. 

A single default code across all studies, or a coder unfamiliar with the 93306/93307/93308 split, can quietly leak revenue for months before anyone catches it.

MedHeave operates as an embedded revenue cycle department inside cardiology practices, with AAPC-certified coders who handle CPT assignment, modifier validation, and NCCI compliance on every echocardiography claim before submission.

• Dedicated account managers with direct access (Monday–Friday, 9–5 EST)
• Denials addressed within 72 hours with payer-specific appeal templates
• Claims submitted within 24–48 hours of signed encounter notes
• 90%+ first-pass rate across all claim types
• 80%+ denial overturn rate

If your cardiology practice is dealing with echo downcodes, add-on code denials, or modifier confusion, contact MedHeave to see how a structured billing process closes those gaps.

Frequently asked questions

Here are some commonly asked questions on this topic: