Cardiology is one of the highest-audit specialties due to the volume of diagnostic testing, high-value procedures, complex bundling rules, and wide variation in physician documentation styles. RAC, MAC, commercial payers, CERT, ZPIC/UPIC, and OIG compliance units frequently review cardiology claims.
This checklist outlines major audit triggers, documentation must-haves, and coding scenarios that require special attention across non-invasive diagnostics, nuclear imaging, E/M, interventional cardiology, electrophysiology, and device management.
High-Level Audit Risk Categories in Cardiology
Auditors typically target:
1. Overuse or Misuse of Diagnostic Testing
Especially:
- Stress tests
- Echo and Doppler studies
- Nuclear cardiology (SPECT/PET)
- Holter / extended ECG services
- ABI / vascular ultrasound
2. Documentation Insufficiencies
Missing:
- Indications
- Interpretation elements
- Signatures
- Medical necessity justification
3. Component Billing Errors
Incorrect use of:
- 26 (professional)
- TC (technical)
- Global billing
4. Modifier Misuse
Especially 25, 59, XS, RT/LT, 76/77, 24/57/79.
5. Invasive Procedure Bundling Errors
Cath lab, PCI, EP, PVI, and device-related services are heavily audited.
6. Upcoding / Downcoding
Missing documentation to support complete vs limited, or single vs multiple studies.
The following sections provide specific, detailed triggers + required documentation for each cardiology area.
Echocardiogram & Doppler (TTE/TEE) Audit Triggers
Risk Trigger 1: Using 93306 without documenting Doppler + color flow
93306 requires:
- 2D
- M-mode (if used)
- Spectral Doppler
- Color flow Doppler
- Missing any of these may lead to downcoding to 93307 or 93308.
Documentation Must Include:
- Valve morphology + function
- Chamber dimensions
- LV function + EF
- Doppler velocities/gradients
- Color flow interpretation
- Pericardial findings
- Aortic root and IVC when medically relevant
Risk Trigger 2: Billing limited echo (93308) repeatedly without justification
Repeated limited studies within short intervals flag:
- Overutilization
- Lack-of-medical-necessity audits
Risk Trigger 3: TEE reports missing sedation information
Required elements:
- Sedation type & dosage
- Probe insertion details
- Indications
- Complete interpretation
- Complications (if any)
Stress Testing Audit Triggers (93015–93018 + Stress Echo)
Risk Trigger 1: Stress tests without documented indications
Auditors commonly deny stress tests with indications such as:
- “Routine follow-up”
- “Check-up”
- “Chest pain” without characterization
Indications must include:
- Symptoms (exercise intolerance, dyspnea, exertional pain)
- Risk factors
- Equivocal ECG/Echo findings
- Preoperative assessment (with justification)
Risk Trigger 2: Billing 93015 when components are divided
Use only when:
- Supervision
- ECG tracing
- Interpretation
- are done by the same entity.
Risk Trigger 3: Stress echo without required stress parameters
MUST include:
- Type of stress (exercise or pharmacologic)
- Duration, METs, peak HR/BP
- Reason for termination
- Baseline & post-stress echo findings
- Wall motion analysis
Missing wall motion assessment is a leading audit failure.
Nuclear Cardiology (SPECT/PET) Audit Triggers
Risk Trigger 1: Incorrect use of 78451 vs 78452
- 78451 = single study
- 78452 = multiple studies
- If rest + stress were done → 78452 only.
Risk Trigger 2: Missing tracer dose + timing documentation
Auditors check for:
- Radiopharmaceutical name
- Dose (mCi)
- Injected times
- Imaging start times
Risk Trigger 3: Missing stress protocol details
Especially for pharmacologic stress.
Risk Trigger 4: Overutilization of nuclear overecho
Auditors compare:
- Prior stress echo or TTE results
- Clinical appropriateness
Prior authorization is crucial with commercial payers.
Cardiac Catheterization & PCI Audit Triggers
Cardiac catheterization is one of CMS’s most scrutinized services due to bundling rules.
Risk Trigger 1: Billing diagnostic cath when prior images exist
Diagnostic cath is NOT billable if:
- Recent angiography exists (90–180 days depending) AND
- No change in clinical status AND
- The decision for PCI was already made
Documentation must explicitly state:
- Why was repeat angiography necessary
- What changed clinically
Risk Trigger 2: Unbundling PCI components
PCI includes:
- Catheter placements
- Angioplasty
- Imaging used to guide therapy in the same vessel
IVUS/OCT + FFR are separately billable only when medically necessary and documented.
Risk Trigger 3: Incorrect coronary modifiers
Required for each treated vessel:
- LD (LAD)
- LC (circumflex)
- RC (right coronary)
- LM (left main, payer dependent)
- RI (ramus intermedius, payer dependent)
Missing or mismatched modifiers → automatic denials.
Risk Trigger 4: Lack of medical necessity for staged PCI
Auditors flag staged PCI within 90 days unless:
- Clearly staged for clinical reasons
- Documented as staged in the original cath report
- Different lesions were treated
Modifiers:
- 58 = staged
- 78 = complication requiring return to the cath lab
Electrophysiology (EP) Audit Triggers
Risk Trigger 1: Ablation procedures without documented arrhythmia
Documentation must include:
- Type of arrhythmia (AF, SVT, VT, atrial flutter)
- Evidence of arrhythmia
- Mapping performed
- Ablation details
- Endpoints & post-ablation outcomes
Risk Trigger 2: Mapping codes improperly billed
If mapping is bundled into the primary ablation code, separate billing is disallowed.
Risk Trigger 3: Add-on EP codes without supporting documentation
Examples:
- Additional linear lesions
- 3D mapping
- Intracardiac echo
- Ensure clear indication & benefit.
Pacemaker & ICD Audit Triggers
Risk Trigger 1: Generator changes without ERI/EOL documentation
MUST include:
- Battery life
- Generator status
- ERI/EOL evidence from interrogation
Risk Trigger 2: Billing lead replacement vs repositioning incorrectly
- Replacement = removal + insertion
- Reposition = adjustment
Misclassification is a major audit target.
Risk Trigger 3: Interrogation vs programming confusion
- Interrogation = review only
- Programming = actual parameter changes
Must document specific setting changes for programming codes.
Risk Trigger 4: Missing device serial numbers
Implant and revision procedures require:
- Lead serial numbers
- Generator model + serial
- Manufacturer
Peripheral Vascular Intervention (PVI) Audit Triggers
Risk Trigger 1: Wrong initial vs add-on code assignment
Each territory (iliac, fem-pop, tibial-peroneal) allows one initial code per session.
Risk Trigger 2: Poor documentation of vessel/segment
Reports must identify:
- Vessel
- Segment
- Lesion length
- % stenosis
- Pre/post results
Risk Trigger 3: Using atherectomy + stent combination codes without justification
E.g., 37227 or 37235 requires documentation of both atherectomy AND stenting in the same vessel.
Risk Trigger 4: Unsupported diagnostic angiography
Rarely separately billable unless criteria are met.
E/M Visit Audit Triggers (Office & Inpatient)
Risk Trigger 1: Modifier 25 misuse
Modifier 25 should only be used when:
- A procedure is performed
- AND a significant, separately identifiable E/M occurs
Auditors look for:
- Template-based notes
- Bullshit/filler symptoms
- No separate assessment/plan beyond procedural consent
Risk Trigger 2: Use of time-based coding without total time documentation
For time-based visits, you must include:
- Total time spent
- What time was spent doing (counseling, data review, care coordination)
Risk Trigger 3: High-level coding (99214–99215 / 99223)
Expect to justify:
- Complexity
- Risk
- Data review
- Decision-making elements
Telehealth Cardiology Audit Triggers
Risk Trigger 1: Missing patient consent documentation
Required once per year by most payers.
Risk Trigger 2: Incomplete telehealth-specific documentation
Must state:
- Location of the patient
- Location of clinician
- Mode of telehealth (audio or audio/video)
Risk Trigger 3: Billing in-person-only codes via telehealth
E.g., stress test monitoring or interpretation without proper data transmission.
General Compliance Checklist (Daily Use)
Documentation MUST:
- Include complete indications
- Identify the anatomy or vessel
- Include quantifiable findings (severity, size, gradients, EF, etc.)
- Reflect interpretation and medical decision-making
- Be signed and dated
- Match the CPT/HCPCS codes billed
Coding MUST avoid:
- Double-billing bundled services
- Using modifiers to bypass NCCI edits without justification
- Unnecessary add-on codes
- Billing diagnostics without required interpretation
Operational MUST:
- Track global periods
- Maintain prior authorization logs
- Match ordering vs interpreting provider roles
- Validate technical vs professional components
- Reconcile radiopharmaceutical doses and units
Conclusion
Cardiology billing carries significant audit exposure because of high-cost imaging, complex procedural coding, and dependencies on detailed physician documentation. Many denials and audit findings stem from missing indications, unclear vessel anatomy, incorrect CPT selection, or misuse of modifiers.
Standardizing report templates, training clinicians on documentation essentials, and performing internal audits greatly reduces risk. Practices often collaborate with specialized cardiology RCM teams—such as Global Tech Billing LLC—to maintain accurate, compliant, audit-ready workflows.
FAQs
1. What is the biggest audit trigger in cardiology?
Missing or insufficient medical necessity documentation for diagnostic testing and imaging.
2. Why are nuclear cardiology studies frequently audited?
Because they involve high cost, strict indications, and complex multi-phase CPT codes.
3. How can PCI documentation fail an audit?
When vessel anatomy, stenosis %, modifiers, or medical necessity for staged PCI are not clearly documented.
4. What is the difference between interrogation and programming audits for device checks?
Programming must show parameter changes; interrogation requires review only.
5. Why do stress tests often get denied?
Insufficient symptoms, vague indications, or incomplete stress parameters.
6. Are diagnostic angiograms always billable with PCI?
No. They require separate indications and decision-making criteria.
7. Why is modifier 25 heavily audited in cardiology?
It is often overused for visits that do not meet “significant and separately identifiable” criteria.
8. What documentation helps reduce audit risk across cardiology?
Clear indications, vessel specificity, complete interpretations, quantifiable findings, and accurate CPT alignment.
