10 Common Cardiology CPT Code Mistakes

Cardiology billing is among the most fault-prone areas of medical revenue cycle management. From subtle procedural coding to forever-changing CPT guidelines and intense payer scrutiny, even minor documentation breakdowns can result in denials, audits, and lost revenue.

Whatever you're dealing with, from inpatient cath lab visits to outpatient pacemaker follow-ups, precise application of cardiology CPT codes is critical.

1. Inappropriate Utilization of Modifier -25 with E/M Visits

Prevalent Error: Using Modifier -25 on every occasion an E/M and a procedure occur on the same day.

Issue: Overutilization can cause compliance flags, particularly if the services aren't medically unique.

Use -25 only when the E/M is inherently identifiable from the procedure, with documentation to support it.

CMS Modifier 25 Guide (PDF)

2. Billing Global Rather than Component-Based Echo Codes

Practices that bill global echocardiogram codes (e.g., 93306) without executing both technical and professional components are at risk of overpayment or denials.

Best Practice: Append Modifier -26 (professional component) or -TC (technical component) depending on services rendered.

3. Misidentifying Cardiac Catheterization Bundles

Example: Billing 93458 when 93459 is actually correct (because it encompasses left ventriculography).

Cardiac cath codes contain bundled services—errors here can balloon charges or perplex payers.

4. Omitting Split Components in Stress Testing

Cardiac stress testing typically entails three discrete codes:

93016 (supervision)

93017 (tracing)

93018 (interpretation)

Don't fall back on 93015 unless your provider performs all three components in one session.

5. Applying Obsolete Codes for Remote Monitoring

Remote monitoring has received several CPT updates in the past two years. For example:

Pacemaker monitoring: Bill 93294 for remote monitoring every 90 days

RPM codes such as 93297 have a minimum data requirement of 16 days

Certain practices continue to inappropriately bill old codes from 2019, potentially leading to rejections.

6. Inappropriate Application of Modifier -59 and Submodifiers

Excessive use of Modifier -59 to avoid CCI edits is a significant compliance threat.

As an alternative, Medicare promotes X-modifiers, such as:

-XS (separate structure)

-XP (another practitioner)

NCCI Manual – Chapter 1 Modifier Guidelines

7. Under-documenting Time-Based Services

Codes such as 93797 (cardiac rehab) and 99417 (extended E/M) must have explicit time statements.

If time is not documented, the payer may downcode or deny altogether.

Always document:

Start and stop time

Activities done

In-person vs. remote components

8. Coding Device Checks Incorrectly

Error: Billing in-person device checks (93286) when only remote interrogation was done.

Correct: Align the code to both procedure and frequency of the service. For example:

93295 = face-to-face ICD check

93296 = remote ICD check

93297 = ongoing remote monitoring for more than 30 days

9. Payer-Specific LCD Guidelines Ignored

Each procedure—ranging from nuclear stress tests to cardiac CT—has to be supported by payer-specific Local Coverage Determinations (LCDs).

Not aligning the ICD-10 diagnosis with the CPT code equals denial despite the procedure being medically necessary.

Use the CMS LCD Search Tool

10. Forgoing Internal Billing Audits

Certain clinics bill without ever examining their CPT patterns of use. That's risky, particularly in 2025 when audit scrutiny will heighten.

For an example of how to organize internal audits in real life, look at this cardiology billing audit template. It identifies how to detect undercoding, missed modifiers, and non-compliant use of -25 and -59.

Ready to Correct These Errors?

These CPT coding mistakes are more than harmless errors — they can put revenue at risk, trigger audits, and undermine payer trust.

To minimize denials and achieve compliance, it is a good idea to join forces with specialists in cardiovascular billing.

If your clinic is prepared to take charge of its cardiology RCM, this billing solutions team has extensive experience managing everything from claims to coding audits for heart and vascular practices across the country.

References:

• CMS Modifier 25 Guidance (PDF)

• NCCI Modifier Guidelines

• AMA CPT 2025 Updates

• Cardiology Billing Audit Template (Google Sites)