CPT 93325 Billing: Color Flow Doppler Add-On

CPT 93325 is the add-on code for color flow Doppler velocity mapping. Like its spectral counterpart, it is straightforward to bill correctly and very easy to bill wrongly, because the most common base code in cardiology already contains it.

What CPT 93325 covers

93325 is Doppler echocardiography color flow velocity mapping, reported in addition to the code for the echocardiographic imaging. Color flow is the overlay that makes regurgitant jets, shunts and turbulent flow visible, and it is distinct work from spectral Doppler quantification.

Where 93325 belongs, and where it does not

Correct: alongside the base codes CPT lists for it, including the limited transthoracic study 93308, transesophageal and congenital echocardiography, stress echocardiography (93350, 93351) and fetal echocardiography.
Incorrect: alongside 93306, which already includes color flow Doppler.
Incorrect: alongside 93307. CPT excludes the pairing; a complete study with Doppler is 93306.

Reimbursement context

93325 is a low-value line that matters through volume. Payment follows the CMS Physician Fee Schedule and varies by locality.

Documentation requirements

Color flow findings named explicitly, not folded into a general statement about Doppler.
Description of any regurgitation, shunt or turbulent flow identified, with severity where assessed.
The base study documented in full.
Retained images supporting the color flow findings.
A signed interpretation covering those findings.

Common denials and the exact fix

Billed with 93306

Color flow Doppler is already inside 93306, so the add-on denies with no override available.

Fix: remove the line. Separate reporting requires a base code that genuinely excludes Doppler.

Add-on billed without a base code

93325 cannot stand alone on a claim.

Fix: confirm an eligible base code is present for the same date of service.

Modifier 51 appended

Add-on codes are exempt from multiple-procedure reductions.

Fix: submit with no 51.

Color flow not distinguished from spectral Doppler in the report

Where both add-ons are billed, a report that refers only to "Doppler" supports neither cleanly.

Fix: name spectral and color flow findings separately in the report template.

Modifier rules

51: never, as with all add-on codes.
26 / TC: follows the base study's component split.
59 / XE / XP / XS / XU: not an override for the 93306 edit.

NCCI bundling edits

93325 with 93306: included, no modifier override.
93325 with 93307: not reported together per CPT.
93325 with 93308: reportable where color flow was performed and documented.
93325 with 93320: both reportable with an eligible base code when both were performed and documented.
93325 with 93350 or 93351: stress echocardiography codes appear on its companion list, so color flow performed and documented during the stress study is reportable.

These are add-on codes. They never stand alone, they never carry modifier 51, and they are never reported with 93306, which already includes them, or with 93307, which CPT excludes.

Frequently asked questions

Why does CPT 93325 deny when billed with 93306?

Because 93306 already includes color flow Doppler. The add-on duplicates work the base code has already paid for, and the NCCI edit carries no modifier override, so no modifier will make the pair payable.

Which base codes make 93325 payable?

The base codes CPT lists for it: the limited transthoracic study 93308, transesophageal and congenital echocardiography, stress echocardiography 93350 and 93351, and fetal echocardiography. It is never reported with 93306, which already includes color flow Doppler, or with 93307, which CPT specifically excludes.

Can 93320 and 93325 both be billed on the same study?

Yes, when both spectral Doppler and color flow Doppler were genuinely performed and separately documented alongside an eligible base code. They describe different work, so reporting both is appropriate where the record supports each.

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 93306. Complete TTE with spectral and color flow Doppler.
CPT 93320. Spectral Doppler add-on.
CPT 93308. Limited or follow-up echo.

CPT 93325: Doppler Echocardiography, Color Flow Velocity Mapping