CPT 93320 is the add-on code for spectral Doppler echocardiography. It is a small line item with an outsized denial rate, because it is routinely attached to a base code that already contains it. Getting 93320 right is mostly about knowing which base code it is sitting next to.
What CPT 93320 covers
93320 is Doppler echocardiography, pulsed wave and/or continuous wave with spectral display, complete, reported in addition to the code for the echocardiographic imaging. It measures blood flow velocity and direction, which is how gradients, valve areas and diastolic function get quantified.
It has a limited companion, 93321, for follow-up or limited spectral Doppler. Both are add-on codes and both follow the same rules.
Where 93320 belongs, and where it does not
- Correct: alongside the base codes CPT lists for it, including transesophageal echocardiography, congenital transthoracic echocardiography (93303, 93304), stress echocardiography (93350, 93351), and the limited transthoracic study 93308.
- Incorrect: alongside 93306, which already includes spectral and color flow Doppler.
- Incorrect: alongside 93307. CPT excludes the pairing; a complete study with Doppler is 93306.
Reimbursement context
93320 carries modest value on its own but adds up quickly across an echo lab's volume, which is why both the denials and the missed captures are worth quantifying.
2026 Medicare RVUs for CPT 93320
| CPT 93320: 2026 Medicare RVUs (national, before GPCI) | ||||||
|---|---|---|---|---|---|---|
| Line | Work | PE, non-facility | PE, facility | Malpractice | Total, non-facility | Total, facility |
| Global (no modifier) | 0.37 | 1.15 | NA | 0.02 | 1.54 | NA |
| Professional (modifier 26) | 0.37 | 0.14 | 0.14 | 0.01 | 0.52 | 0.52 |
| Technical (modifier TC) | 0.00 | 1.01 | NA | 0.01 | 1.02 | NA |
Source: CMS CY 2026 PFS Relative Value File, RVU26D (October release, published 08/26/2026). RVUs are national and unadjusted; commercial payers set their own rates.
In the 2026 CMS relative value file, CPT 93320 carries 0.37 work RVUs and 1.54 total RVUs when billed globally in a non-facility setting. The global line is NA in a facility, because there the physician bills the professional component only and the facility bills the technical side. Its PC/TC indicator is 1: the code splits into a professional component (modifier 26, 0.52 total RVUs) and a technical component (modifier TC, 1.02 total RVUs), and the global line is billed only when one entity does both. Its global indicator is ZZZ: it is an add-on code, always reported with its primary service and falling inside that service's global period.
To turn RVUs into payment, each component is multiplied by your locality's geographic practice cost index, the three are added, and the sum is multiplied by the 2026 conversion factor: $33.4009, or $33.5675 for qualifying APM participants (CMS-1832-F; CMS fact sheet). The CMS Physician Fee Schedule Look-Up Tool runs that calculation for your locality.
Documentation requirements
- Spectral Doppler findings named explicitly as spectral, pulsed wave or continuous wave.
- Velocities and gradients measured, not merely described qualitatively.
- The base study documented in full, since the add-on cannot stand alone.
- Retained images or tracings supporting the Doppler measurements.
- A signed interpretation covering the Doppler findings as part of the study.
Medicare contractor billing articles. Each Medicare Administrative Contractor publishes its own billing and coding articles for this service, and the covered diagnoses differ by jurisdiction. Active examples in the CMS Medicare Coverage Database, checked September 28, 2026: A57306 (Transthoracic Echocardiography (TTE), CGS), A56781 (Transthoracic Echocardiography (TTE), Wellpoint Federal) and A56625 (Echocardiography, Palmetto GBA). Use the article from the contractor that processes your claims.
Common denials and the exact fix
Billed with 93306
The leading echo bundling denial. 93306 already contains spectral Doppler.
Fix: remove the line. A complete transthoracic study with Doppler is 93306 in full; recoding it to 93307 plus add-ons is not allowed. Separate Doppler reporting applies only where the base code is one CPT lists for it, such as a genuinely limited 93308 study.
Add-on billed without a base code
Add-on codes cannot stand alone. A claim carrying 93320 with no echocardiography base code on it rejects.
Fix: confirm the base code is present on the same claim for the same date of service.
Modifier 51 appended
Add-on codes are exempt from multiple-procedure reductions, so a 51 here causes an inappropriate reduction or a rejection.
Fix: submit add-on codes with no 51.
Doppler not separately documented
A report that never names spectral Doppler findings does not support the add-on even where the base code allows it.
Fix: require named Doppler findings with measured values in the report template.
Modifier rules
- 51: never. Add-on codes are exempt.
- 26 / TC: follows the base study's split, matching place of service and equipment ownership.
- 59 / XE / XP / XS / XU: not a route to getting 93320 paid alongside 93306. That edit has no override.
NCCI bundling edits
- 93320 with 93306: included, no modifier override available.
- 93320 with 93307: not reported together per CPT.
- 93320 with 93308: reportable where Doppler was performed and documented.
- 93320 with 93325: both add-ons may be reported with an eligible base code when both were genuinely performed and documented.
- 93320 with 93350 or 93351: stress echocardiography codes appear on its companion list, so spectral Doppler performed and documented during the stress study is reportable.
Frequently asked questions
Why does CPT 93320 deny when billed with 93306?
Which base codes make 93320 payable?
Should modifier 51 be appended to CPT 93320?
What is the difference between 93320 and 93321?
Sources
American Medical Association, CPT 2026 Professional Edition.
Centers for Medicare & Medicaid Services, CY 2026 PFS Relative Value File RVU26D (October release): RVUs, PC/TC indicator and global period for CPT 93320.
Centers for Medicare & Medicaid Services, CY 2026 Physician Fee Schedule final rule, CMS-1832-F: conversion factors.
Centers for Medicare & Medicaid Services, National Correct Coding Initiative Policy Manual for Medicare Services and quarterly procedure-to-procedure edit tables.
Medicare Coverage Database billing and coding articles A57306, A56781, A56625.
CPT® is a registered trademark of the American Medical Association. Payer policy and NCCI edits change quarterly, so check your own contractor before submission. How we verify this guidance.
Related codes
- CPT 93306. Complete TTE with spectral and color flow Doppler.
- CPT 93325. Color flow Doppler add-on.
- CPT 93308. Limited or follow-up echo.
More cardiology code guides
- CPT 93454. Coronary angiography, no heart catheterization.
- CPT 93459. Left heart cath with coronary and bypass graft angiography.
- CPT 93461. Right and left heart cath with coronary and graft angiography.
Related reading
- Cardiology billing & RCM. How we scrub cardiology claims across diagnostics, cath lab, EP and remote monitoring.
- Echocardiography billing: complete vs. limited studies. What separates a defensible complete echo from a limited one.
- TC/26 modifier errors in cardiology. The split-billing mistakes that cost diagnostic practices the most.
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