Cardiology billing sits in the crosshairs of several audit programs simultaneously.
OIG work plans
The Office of Inspector General publishes annual work plans identifying audit focus areas. Cardiology has appeared in OIG work plans for: elective PCI appropriateness, cardiac device implantation compliance with NCD criteria, echocardiography medical necessity, and E&M upcoding patterns.
CMS Targeted Probe and Educate (TPE)
MACs use TPE to identify providers with billing patterns outside norms. The workflow:
- Round 1: Audit of 20-40 claims. If error rate exceeds threshold, MAC provides education and a defined improvement window.
- Round 2: Repeat if Round 1 problems persist. Additional education and monitoring.
- Round 3: Extended sample and potential referral for additional oversight (prepayment review, CERT review, or referral to law enforcement in cases suggesting fraud rather than error).
Passing Round 1 typically clears the practice from the TPE cycle. Failing Round 3 can trigger prepayment review where every claim is manually reviewed before payment, which effectively shuts down cash flow.
Recovery Audit Contractors (RACs)
RACs are contingency-fee auditors approved by CMS to review claims for improper payments. Because RACs earn fees on recovered payments, they aggressively review high-dollar patterns. Cardiology RAC issues have included:
- Echocardiography frequency (repeat studies within LCD windows without clinical-trigger documentation)
- Elective PCI for stable ischemic heart disease indications
- Cardiac device implantation compliance with NCD criteria
- Modifier misuse patterns
RACs can review claims up to 3 years old under current rules, meaning recoupment demand letters can arrive years after the service.
Commercial payer audits
Commercial payers conduct their own audits separately from CMS programs. Post-payment audits (recoupment demands after payment) are common. Payer audit rights are governed by contract, and most cardiology practices' contracts allow audits with modest notice.
The highest-risk cardiology billing patterns
E&M level upcoding
The 2021 E&M revision removed history and physical exam from level selection, making MDM and time the drivers. Auditors compare the documented MDM (or time) against the billed level. A practice consistently billing 99214 or 99215 for encounters where documentation shows moderate or lower complexity triggers pattern-level scrutiny.
Echocardiography medical necessity and frequency
Repeat echos within LCD frequency windows (typically 90-180 days) without clinical-trigger documentation are a common audit target. The trigger documentation must show a specific clinical change: new symptom, medication adjustment, post-procedure follow-up, or acute event.
Elective PCI for stable ischemic heart disease
Appropriate use criteria for elective PCI have tightened since the ISCHEMIA trial. Documentation must support the ischemic burden on noninvasive testing, prior medication trial, and shared decision-making. Cases with borderline ischemic burden or minimal medication trial before intervention face audit scrutiny.
Cardiac device implantation appropriateness
Pacemaker and ICD implants under NCD criteria require specific documentation of indications. Modifier KX is required on pacemaker claims (CPT 33206, 33207, 33208) certifying compliance. Failure to meet NCD criteria produces post-payment recoupment when audit review finds documentation does not support the indication.
Modifier misuse (25, 26, 59, 78, 79)
Modifier 25 (significant separately identifiable E&M on same day as procedure) is heavily audited. Documentation must clearly show the E&M work was distinct from the procedure's inherent evaluation. Modifier 26 and TC misuse (billing global when the other component was performed elsewhere) generates duplicate-billing patterns. Modifier 59 (distinct procedural service) is subject to substantial audit scrutiny given its use to unbundle otherwise-bundled services.
Defensive documentation practices
Map documentation to LCD language
When a service is performed under an LCD, use the LCD's language in documentation. If the LCD lists specific covered indications, the documentation should explicitly reference the applicable indication. This makes medical-necessity defense straightforward if the claim is audited.
Document MDM elements explicitly
For E&M coding, document the specific MDM elements: which problems were addressed and their complexity level, what data was reviewed, and the risk assessment. Explicit MDM documentation supports the billed level and defends against upcoding audit findings.
Complete-echo documentation
When billing CPT 93306, the report should explicitly note 2D imaging, M-mode (when performed), spectral Doppler, and color flow Doppler. Missing any complete-echo component while billing 93306 exposes the claim to audit downcoding to CPT 93307 or 93308.
Cath report specificity
Cath reports should explicitly state which coronary arteries were injected, whether LV angiography was performed, whether right heart catheterization was performed, and whether bypass grafts were selectively engaged. That specificity defends the specific cath code selected (93454-93461).
Modifier justification notes
When using modifier 25, add a brief note explaining what E&M work was performed beyond the procedure's inherent evaluation. When using modifier 24 during a global period, note the visit's unrelated clinical purpose. When using modifier 59 or an X modifier, note why the services were distinct.
Contemporaneous documentation
Documentation written at or near the time of service carries substantially more weight in audit review than late addenda. Late addenda are permitted but face audit skepticism, particularly if the addendum appears to be added after audit notification.
Extrapolation risk
If a TPE, RAC, or OIG audit finds a high error rate on a sample, extrapolation applies the error rate to a larger claim universe. A 30% error rate on 40 audited claims can extrapolate to hundreds of thousands of dollars in recoupment when applied to the practice's historical claim volume. Extrapolation defense typically requires statistical challenges to the sample selection and requires legal representation.
Building an internal audit rhythm
Cardiology practices with mature compliance programs typically:
- Audit a random sample of E&M coding monthly (10-25 claims across all providers)
- Audit echocardiography reports quarterly for complete-echo documentation completeness
- Audit cath reports quarterly for code-selection accuracy against report specificity
- Track denial patterns by CARC code and by provider to identify documentation gaps
- Update physician documentation prompts when denial or audit patterns emerge
Internal audit is dramatically cheaper than defending an external audit finding. Practices with disciplined internal audit typically clear external audits without extrapolation and maintain lower baseline denial rates.