Echocardiogram billing: CPT 93306, 93307, 93320, and 93325 explained.
Echocardiography is cardiology's highest-volume diagnostic study, and the Doppler add-on codes are one of the specialty's most reliable, most avoidable denial sources: 93320 and 93325 report work that's already included in 93306's own definition. This guide covers the full code family and exactly when each add-on is and isn't separately billable.
Key takeaways
- 93306 already includes spectral and color-flow Doppler. Billing 93320 or 93325 alongside it reports the same work a second time.
- 93307/93308 don't include Doppler — that's exactly when the add-on codes belong on the claim, if Doppler was separately performed and interpreted.
- All nine cardiac structures have to be addressed in the report to support a complete-study code; a partial report supports only the limited-study codes.
- The component split (26/TC) applies here exactly as it does everywhere else in cardiology — equipment ownership decides it, not who's most convenient to bill.
The core code family
| Code | Service | Doppler included? |
|---|---|---|
93306 | Complete transthoracic echo (TTE), real-time with 2D image documentation, plus spectral and color-flow Doppler | Yes, built into the code |
93307 | Complete TTE, no Doppler | No — add separately if performed |
93308 | Follow-up or limited TTE, no Doppler | No — add separately if performed |
93320 | Doppler echocardiography, pulsed wave and/or continuous wave, spectral display; complete | — add-on code |
93325 | Doppler echocardiography, color flow velocity mapping | — add-on code |
The 93306 + 93320/93325 trap
This is the single most common echo billing error we see, and it's entirely avoidable: 93306's own definition already includes spectral and color-flow Doppler, so appending 93320 or 93325 to a claim that also bills 93306 reports the same clinical work twice. ⚠️ Billing-industry sources consistently describe this pair as bundled under a modifier indicator that cannot be overridden by any modifier — this build attempted to confirm that exact indicator value directly against CMS's primary NCCI PTP edit file and could not (every automated retrieval attempt against cms.gov returned an access error). Treat the pairing as very unlikely to be separately payable under any circumstance, and confirm the current value in the CMS NCCI PTP Edits Lookup Tool before building a scrubber exception for it.
The add-on codes belong on a claim only when the base code is 93307 or 93308 — the versions that don't already include Doppler — and the Doppler study was genuinely performed and separately interpreted. If no Doppler was performed or documented at all, bill 93307 alone with no add-on.
Documentation that supports a complete study
A report supporting 93306 needs to address all nine standard cardiac structures: left atrium, right atrium, left ventricle, right ventricle, the aortic valve, mitral valve, and tricuspid valve, the aorta, and the pericardium, along with 2D imaging, M-mode where performed, and both spectral and color-flow Doppler. A report that's missing structures, or that only partially addresses Doppler, supports the limited or follow-up codes (93308), not the complete study code, regardless of what was billed — this is exactly the kind of gap an auditor checks first.
Component split applies here too
Like every other diagnostic study in cardiology, echo billing splits by equipment ownership and site of service. Bill globally only when your practice owns the equipment, employs the sonographer, and your physician performs the interpretation. Bill modifier 26 when your physician reads a study acquired on equipment the practice doesn't own — the normal case for hospital-based reads. The full component-split logic, including the most common error of billing globally on rented or hospital equipment, is covered in our cardiology modifiers guide.
Run a report of every claim in the last quarter that billed 93306 alongside 93320 or 93325. If any exist, that's found revenue leakage in reverse — those claims either got denied (lost staff time re-working them) or, worse, got overpaid and are now a recoupment risk. Either way, fixing the scrubber rule that let them through is higher-value than working the individual claims.
Echo claims denying or getting flagged for overpayment?
We'll audit your echo billing for the 93306/93320 pattern and the component-split errors that cost the most in this code family.
Frequently asked questions
Can we ever bill 93320 with 93306?
Billing-industry sources consistently describe this pairing as bundled with no override available under the applicable NCCI edit — 93306 already includes spectral and color-flow Doppler in its own definition, so 93320 would be reporting the same work twice. This build could not confirm the specific modifier indicator against CMS's primary NCCI file directly, so verify the current value in the CMS NCCI PTP Edits Lookup Tool before relying on it, but treat 93320-with-93306 as very unlikely to be separately payable under any circumstance.
What's the actual difference between 93306 and 93307?
93306 is a complete transthoracic echo that includes spectral and color-flow Doppler as part of the code's own definition. 93307 is a complete or follow-up/limited TTE without Doppler. If Doppler was performed and documented, 93306 already covers it; if it wasn't, or if you're billing a limited follow-up study, 93307 is correct — and only 93307 (or 93308) can be paired with the separate Doppler add-on codes 93320/93325 when those studies were genuinely performed and interpreted separately.
What documentation does a complete echocardiogram need to support 93306?
The report needs to address all nine standard cardiac structures — left and right atria, left and right ventricles, the aortic, mitral, and tricuspid valves, the aorta, and the pericardium — with 2D imaging, M-mode where performed, and spectral and color-flow Doppler. A report missing structures or Doppler elements supports the more limited 93307/93308 codes, not 93306, regardless of what was billed.
Verify before billing. CPT is a registered trademark of the American Medical Association; codes here are paraphrased, not reproduced from the CPT Professional edition. NCCI edits and payer coverage policy change. This page reflects standard industry practice and is provided for general education — confirm the current edit status for any code pair before submitting claims.