CPT 93308 Billing: Limited or Follow-Up Echo

CPT 93308 is the follow-up or limited transthoracic echocardiogram. It is treated as a consolation prize in a lot of practices, which is exactly backwards: 93308 is a correct code, and using it when the documentation calls for it is considerably cheaper than defending a sample of complete studies on post-payment review.

What CPT 93308 covers

93308 is transthoracic echocardiography, real-time with image documentation (2D), including M-mode recording when performed, follow-up or limited study. It describes a focused look that answers a specific question rather than a full structural assessment.

Two very different situations land here:

A genuinely focused study: a re-look at ejection fraction, a pericardial effusion check, a targeted valve question.
A study intended to be complete that the documentation does not support: required structures not addressed, with no reason recorded for the omission.

Reimbursement context

93308 pays less than the complete codes, which is precisely why it gets avoided. The economics only work in favour of upcoding until a payer samples the complete-echo population, at which point the recoupment covers several years of the difference. Payment follows the CMS Physician Fee Schedule and varies by locality.

Documentation requirements

The specific clinical question the study was performed to answer.
The structures actually examined and the findings for each.
Reference to the prior study where this is a follow-up, including what changed.
Where Doppler was performed, findings named as spectral or color flow so add-ons are supportable.
Retained images available for review.
A signed interpretation naming the study performed as limited or follow-up.

Common denials and the exact fix

Frequency or duplicate denial on a repeat study

A second echo close behind the first denies unless the record explains why it was needed.

Fix: document the clinical change that prompted the repeat. A scheduled interval re-look without a change in status is difficult to defend.

Billed alongside a complete echo for the same session

One study produces one code. A limited study performed as part of a complete study is not separately reportable.

Fix: report the single code matching what was done.

Limited study billed as complete

The inverse error, and the expensive one. It pays on submission and fails on audit.

Fix: a scrub rule that compares the structures addressed in the report against the complete-study requirements before the claim goes out.

CO-50: diagnosis does not support the study

Limited studies face the same medical-necessity test, and a vague indication draws a denial.

Fix: code the specific question that prompted the study.

Modifier rules

26 / TC: split by setting and equipment ownership.
76 / 77: repeat study by the same or another physician, with a documented clinical trigger. This is the modifier pair that matters most on 93308.
51: not appended to add-on codes.
59 / XE / XP / XS / XU: rarely applicable.

NCCI bundling edits

93308 with 93320 or 93325: separately reportable, because 93308 excludes Doppler.
93308 with 93306 or 93307: one study, one code.
93308 with 93350 or 93351: stress echocardiography includes the echo imaging.
Repeat studies within short intervals are subject to payer frequency policy rather than NCCI alone.

Frequently asked questions

When is 93308 the correct code?

When the study was focused on a specific clinical question rather than a full structural assessment, or when it was a follow-up look at a known finding. If the required structures of a complete study were not examined and no reason was documented for the omission, 93308 is the only defensible code even where the intent was a complete study.

Can I bill 93320 or 93325 with 93308?

Yes. 93308 does not include Doppler, so when spectral or color flow Doppler is separately performed and documented, the add-on codes are separately reportable. 93308 is the transthoracic code these add-ons are reported with: 93306 already includes Doppler, and CPT does not allow the add-ons with 93307.

Why did my repeat echo deny?

A second study close behind the first draws a frequency or duplicate denial unless the record explains the clinical change that prompted it. Documenting the change in status is what makes the repeat payable, and if the repeat was a focused re-look rather than a full restudy then 93308 is also the correct code for it.

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 93307. Complete TTE without Doppler.
CPT 93320. Spectral Doppler add-on.

CPT 93308: Transthoracic Echocardiography, Follow-Up or Limited Study