Cardiology Medical Billing Guide: EKG, Echo & Stress Test Coding

Cardiology billing runs on a mix of diagnostic testing codes that split into technical and professional components — and getting that split wrong is one of the fastest ways to either underbill or trigger a denial.

A cardiology practice's revenue depends heavily on correctly coding the diagnostic tests that make up most of its visit volume — EKGs, echocardiograms, and stress tests each have their own coding structure.

EKG Coding

A standard 12-lead EKG is billed as CPT 93000 for the global service (tracing plus interpretation and report). When the technical and professional components are split between two different entities — common when a hospital owns the equipment but an outside cardiologist reads the results — 93005 bills the tracing only and 93010 bills the interpretation only.

Echocardiogram Coding

CPT 93306 covers a complete transthoracic echocardiogram — 2D imaging, M-mode recording, and spectral and color flow Doppler, with interpretation and report. This is the standard code for a comprehensive echo; more limited echo studies have their own separate codes and shouldn't be billed as 93306 if the full study wasn't performed.

Stress Test Coding: Four Codes, Not One

Stress testing has four separate CPT codes depending on which components were performed and by whom:

93015 — Global code covering supervision, tracing, and interpretation

93016 — Physician supervision only

93017 — Tracing only

93018 — Interpretation and report only

Billing 93015 when your practice only performed one component of the test is a straightforward but common overbilling error, particularly when a stress test is split between a referring practice and a cardiology group.

Cardiac Catheterization

Catheterization coding depends specifically on which heart chambers were accessed and whether coronary angiography was performed. Left heart catheterization with coronary angiography is billed as 93458; when both right and left heart catheterization are performed along with coronary angiography, 93460 applies instead. Using the wrong code for the chambers actually accessed is a common source of cardiology claim denials.

Common ICD-10 Pairings

Cardiology diagnostic workups frequently pair these CPT codes with chest pain codes (R07.9 and related) and atrial fibrillation codes (I48.91 and its type-specific variants) — accurate diagnosis coding alongside the correct procedure code is what supports medical necessity for higher-cost testing like echo and catheterization.

Documentation Tips

Because so much of cardiology billing depends on exactly which component of a test was performed, documentation should specify supervision, tracing, and interpretation separately rather than just noting "stress test performed" — that level of detail is what determines which of the four stress test codes actually applies.

Get a free practice audit and we'll review how accurately your cardiology practice's diagnostic testing codes reflect what's actually documented for each component.

Frequently Asked Questions

What's the difference between CPT 93015 and 93017? 93015 is the global stress test code covering all components; 93017 covers only the tracing portion, used when supervision and interpretation are billed separately by other providers.

Does 93306 cover a limited echocardiogram? No — 93306 is specifically for a complete transthoracic echo with full 2D, M-mode, and Doppler components; limited studies have their own distinct codes.

How is cardiac catheterization coding determined? By which chambers were accessed (left only, or combined right and left) and whether coronary angiography was performed alongside it.

What's the most common EKG billing error? Billing the global code (93000) when the technical and professional components were actually performed by two different entities, which should instead be split between 93005 and 93010.

Do cardiology claims need diagnosis-specific documentation for testing to be paid? Yes — payers expect the ICD-10 diagnosis to reasonably support the medical necessity of the specific cardiac test billed, especially for higher-cost studies like echo and catheterization.