CPT 93306 Billing: Complete TTE With Doppler

CPT 93306 is the complete transthoracic echocardiogram with spectral and color flow Doppler, and it is the highest-volume echo code in most cardiology practices. Nearly all of its denials come from two places: Doppler add-ons billed next to a code that already includes them, and a study coded complete that the report does not support.

What CPT 93306 covers

93306 is transthoracic echocardiography, real-time with image documentation (2D), including M-mode recording when performed, complete, with spectral Doppler and with color flow Doppler. All three pieces (the complete 2D study, spectral Doppler, and color flow Doppler) live inside the one code.

"Complete" has a specific meaning. The study attempts evaluation of the left and right atria, the left and right ventricles, the aortic, mitral and tricuspid valves, the pericardium, and the adjacent portions of the aorta. M-mode is performed when appropriate but is not required to assign the complete code. Where a structure could not be adequately visualised, the report should say so and say why. A documented unsuccessful attempt still supports the complete code. Silence does not.

Choosing between 93306, 93307 and 93308

This is where most echo revenue is lost, and the two failure modes are different from each other:

No Doppler performed or documented goes to 93307, the complete study without Doppler.
Complete study with spectral and color flow Doppler goes to 93306.
Focused or follow-up study answering a specific question goes to 93308.

93307 is about the absence of Doppler. 93308 is about the absence of a complete structural exam. Missing Doppler on an otherwise complete study is 93307, not 93308.

A limited re-look at LV function on a patient who had a full study last month is 93308 whether or not Doppler was used. Getting this pair the wrong way round is a quiet, repeatable revenue error in both directions.

Reimbursement context

93306 splits into a professional and a technical component, and the split is where most of the dollar value sits. Physician payment follows the CMS Physician Fee Schedule and varies by locality. Pull the current allowable for your locality from the CMS Physician Fee Schedule Look-Up Tool rather than working from a national average.

Documentation requirements

An indication explaining why the study was ordered, coded to a specific cardiac diagnosis.
Evidence in the report addressing each required structure: left and right atria, left and right ventricles, aortic, mitral and tricuspid valves, pericardium, adjacent aorta.
An explicit note wherever a structure could not be adequately visualised, with the reason.
Spectral Doppler findings and color flow Doppler findings, named as such, if 93306 is billed.
Measurements supporting the assessment: chamber dimensions, ejection fraction with the method used, valve gradients and velocities as applicable.
Retained images available for review.
A signed interpretation naming the study performed.

Common denials and the exact fix

Double-billed Doppler: 93320 or 93325 reported with 93306

The leading NCCI-related denial in echo billing. 93306 already contains spectral Doppler and color flow Doppler, so the add-on line bills the same work a second time and denies on every claim.

Fix: remove the add-on lines. There is no modifier that makes this pair payable, because the edit carries no modifier override. +93320 and +93325 are reported only with the base codes CPT lists for them, such as the limited study 93308 and the transesophageal, congenital and stress echo codes. They are never reported with 93306, and never with 93307 either: CPT excludes that pairing, because a complete study with Doppler is 93306.

Study coded complete, report does not support it

If the report does not address the required structures and does not explain why any of them could not be seen, the complete code is not defensible on audit even when it pays on first submission.

Fix: code the study the report actually supports. 93308 is a correct code, not a fallback. Coding to the documentation is considerably cheaper than repaying a sample of complete-echo claims on post-payment review.

Missing or mismatched 26 / TC

In a facility the interpreting physician reports 93306-26 and the facility bills the technical component. A global 93306 submitted from a facility place of service denies.

Fix: align the modifier, the place of service and equipment ownership. This is among the highest-volume denial sources in echo billing, and it is entirely preventable at the scrub stage.

CO-50: diagnosis does not support the echo

Screening-flavoured or non-cardiac diagnoses draw medical-necessity denials, and many MACs publish a Local Coverage Determination listing covered indications for echocardiography.

Fix: code the specific cardiac indication, and check your MAC's echocardiography LCD before appealing rather than after.

Repeat echo inside a short interval

A second complete study close behind the first draws a frequency or duplicate denial unless the record explains the clinical change that prompted it.

Fix: document the change in status. If the repeat is a focused re-look rather than a full restudy, it is 93308.

Modifier rules

26 / TC: the core modifier decision on this code. Must match the billing entity, the place of service and equipment ownership.
59 / XE / XP / XS / XU: rarely applicable to 93306, and never a route to getting 93320 or 93325 paid alongside it.
76 / 77: repeat procedure by the same or another physician, for a genuine second study with a documented clinical trigger.
51: multiple procedures. Not appended to add-on codes such as 93320 or 93325.
25: belongs on the E/M, not on the echo, and only where a separately identifiable evaluation beyond the study was performed.

NCCI bundling edits

93320 and 93325 are components of 93306. The edit carries no modifier override, so the add-on denies every time.
93306 and 93308 for the same session report one study. Bill the code that matches what was done, not both.
93350 / 93351 (stress echocardiography) include the echo imaging performed for that study. A resting complete echo on the same day needs a separately documented indication.
Congenital echo codes are not reported alongside 93306 for the same session.
Edits update quarterly, so check the current NCCI table before assuming a pair is still payable.

Frequently asked questions

Can I bill 93320 or 93325 with CPT 93306?

No. 93306 already includes spectral Doppler and color flow Doppler, so adding 93320 or 93325 bills the same work twice and the add-on line denies. The NCCI edit carries no modifier override, which means there is no modifier that makes the pair payable. Those add-ons are reported only with the base codes CPT lists for them, such as the limited study 93308 and the transesophageal, congenital and stress echo codes. They are not reported with 93307 either, because a complete study with Doppler is 93306.

What is the difference between 93306, 93307 and 93308?

93306 is a complete transthoracic echocardiogram with spectral and color flow Doppler. 93307 is the same complete study performed without Doppler. 93308 is a follow-up or limited study answering a focused question. The distinction matters: missing Doppler on an otherwise complete study is 93307, while an incomplete structural exam is 93308.

What makes an echocardiogram complete for CPT 93306?

A complete study attempts evaluation of the left and right atria, the left and right ventricles, the aortic, mitral and tricuspid valves, the pericardium and the adjacent portions of the aorta. If a structure could not be adequately visualised, the report should say so and say why. A documented unsuccessful attempt still supports the complete code; simply not addressing a structure does not.

Does CPT 93306 need modifier 26 or TC?

In a facility setting the interpreting physician reports 93306 with modifier 26 while the facility bills the technical component. When the practice owns the equipment and provides the interpretation, the code is reported globally with no modifier. A global 93306 submitted from a facility place of service denies, and this mismatch is among the highest-volume denial sources in echo billing.

Can a stress echocardiogram and a resting 93306 be billed the same day?

Not routinely. Stress echocardiography codes 93350 and 93351 include the echo imaging performed for that study. A resting complete echo billed on the same day draws scrutiny and typically needs documentation of a separate clinical indication that the stress study did not address.

Sources

American Medical Association, CPT 2026 Professional Edition.
Centers for Medicare & Medicaid Services, National Correct Coding Initiative Policy Manual and quarterly edit tables, cms.gov.
Centers for Medicare & Medicaid Services, Physician Fee Schedule Look-Up Tool, cms.gov.
American College of Cardiology, acc.org. AAPC coding resources, aapc.com.

CPT® is a registered trademark of the American Medical Association. Code descriptors are summarised here for billing guidance and are not a substitute for the current CPT codebook. Payer rules and NCCI edits change quarterly; verify against your own payer policy before submission.

Related codes

CPT 93307. Complete TTE without Doppler.
CPT 93308. Limited or follow-up echo.
CPT 93320. Spectral Doppler add-on.

CPT 93306: Transthoracic Echocardiography, Complete With Doppler