CPT Code 93356: Myocardial Strain Imaging Billing Guide

Key Takeaways

CPT Code 93356 describes myocardial strain imaging using speckle tracking-derived assessment of myocardial mechanics, effective as a Category I code since January 1, 2020

93356 is an add-on code that must always be reported with a primary echocardiography code (93303, 93304, 93306, 93308, 93350, or 93351) and cannot be billed alone. Report 93356 once per imaging session regardless of how many qualifying parent codes are billed

Medicare does not separately reimburse CPT 93356 for outpatient hospitals (facility side); professional billing and commercial payers vary by policy

Pabau’s claims management software helps cardiology practices track add-on code pairings, documentation completeness, and denial patterns for echocardiography billing

Cardiology billing teams consistently report that add-on codes generate a disproportionate share of claim denials. When a service requires a primary procedure code plus a supplemental code, each with its own documentation standard, the margin for error doubles. CPT Code 93356 sits squarely in that category. Introduced as a Category I code on January 1, 2020, it was developed by the American Society of Echocardiography (ASE) and represents one of the first new codes approved for echocardiographic imaging in a decade. Understanding its rules prevents costly denials and ensures compliant revenue capture for myocardial strain assessments.

This reference covers the official code description, add-on code pairing requirements, documentation standards, Medicare and commercial payer reimbursement rules, paired ICD-10 codes, and common denial triggers for CPT Code 93356.

CPT Code 93356: Definition and Official Description

The American Medical Association (AMA) defines CPT Code 93356 with the following official descriptor:

93356: Myocardial strain imaging using speckle tracking-derived assessment of myocardial mechanics (List separately in addition to codes for echocardiography imaging)

Speckle tracking echocardiography works by tracking unique acoustic patterns, called speckles, in the myocardium across sequential ultrasound frames. Software algorithms calculate deformation metrics, most notably Global Longitudinal Strain (GLS), which quantifies how much the heart muscle shortens and thickens during each cardiac cycle. This provides a more sensitive measure of ventricular function than left ventricular ejection fraction (LVEF) alone, particularly in patients with preserved ejection fraction.

The code became Category I effective January 1, 2020, elevating it from research-use status to a billable, reimbursable service. Before that date, cardiologists performing speckle tracking had no dedicated CPT code and could not separately report the service. Now, eligible practices can capture this revenue when the imaging is clinically indicated and properly documented. For practices managing echocardiography procedure codes alongside other cardiology services, understanding 93356’s scope prevents both underbilling and overcoding.

Add-On Code Rules: What CPT 93356 Requires

The plus sign prefix (+93356) is not decorative. It signals that this code is an add-on code, meaning it cannot be submitted on a claim by itself. The AMA requires it to be reported in addition to a primary echocardiography code from the following approved list:

• 93306 – Echocardiography, transthoracic, real-time with image documentation, complete (with or without spectral Doppler and color flow Doppler)
• removed – Echocardiography, transthoracic, real-time, without spectral or color Doppler
• 93308 – Echocardiography, transthoracic, real-time, follow-up or limited study
• 93303 – Echocardiography, transthoracic, for congenital cardiac anomalies, complete
• 93304 – Echocardiography, transthoracic, for congenital cardiac anomalies, follow-up or limited

Submitting 93356 without one of these primary codes on the same claim will result in an automatic denial. The pairing must appear on the same date of service, on the same claim, for the same patient. Claims reviewers and automated edits check for this relationship before adjudication. Using Pabau’s claims management software allows practices to configure code pairing rules so billers receive alerts when 93356 is submitted without its required parent code.

Chart Reference: CPT 93356 Code Summary

The table below summarises the key billing attributes of CPT Code 93356 for quick reference during claim preparation and auditing.

Documentation Requirements for CPT Code 93356

Incomplete documentation is the most common reason for 93356 claim denials. Payers, including Medicare Administrative Contractors (MACs), expect specific elements in the procedure report before approving separate reimbursement for speckle tracking analysis. Generic echocardiography documentation that does not mention speckle tracking is insufficient, even if the analysis was performed.

According to ASE echocardiography coding guidance, the procedure report must include all of the following elements to support billing CPT 93356:

• Explicit statement that speckle tracking was performed – the report must name the specific technique, not simply reference “advanced analysis”
• Quantitative strain values – numerical GLS (Global Longitudinal Strain) measurements must be documented; qualitative descriptions alone (“reduced strain”) do not meet the standard
• The software algorithm or vendor platform used – document which speckle tracking software generated the strain data
• Clinical interpretation – the cardiologist must interpret the strain findings in the context of the patient’s clinical presentation
• Medical necessity statement – the report or associated clinical notes must connect the strain assessment to a specific indication (see ICD-10 pairings below)

Practices using AI-powered clinical documentation tools can build structured echocardiography report templates that prompt providers to capture each required element at the time of service. This approach reduces retrospective documentation fixes and supports HIPAA-compliant documentation workflows that hold up under MAC audits.

Medical Necessity and Paired ICD-10 Codes

Payers require that the diagnosis code on the claim supports the medical necessity of speckle tracking specifically, not just echocardiography in general. Standard indications for transthoracic echocardiography (such as chest pain evaluation) are not automatically sufficient to justify myocardial strain imaging. The diagnosis must reflect a condition where subclinical myocardial dysfunction is clinically relevant.

The following ICD-10 diagnosis codes are among the most frequently paired with CPT Code 93356 in covered claims:

Chemotherapy-induced cardiotoxicity monitoring represents a particularly strong clinical indication. Oncology patients receiving cardiotoxic agents (anthracyclines, HER2-targeted therapies) undergo serial echocardiography, and GLS assessment provides earlier detection of myocardial injury than LVEF monitoring alone. For these patients, accurate EHR integration between oncology and cardiology workflows ensures the relevant oncologic diagnosis codes appear on the cardiology claim to support medical necessity.

Local Coverage Determinations (LCDs) from Medicare Administrative Contractors provide payer-specific guidance on covered indications. Practices should review their MAC’s LCD for echocardiography before billing 93356 for indications beyond cardiomyopathy and heart failure. These policies vary by jurisdiction and are updated periodically by CMS.

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Medicare and Commercial Payer Reimbursement for CPT 93356

Reimbursement for CPT Code 93356 depends on the billing setting and the payer. The professional versus facility billing distinction is critical, and misunderstanding it leads to systematic claim errors.

Professional Billing (Physician Practice)

Cardiologists billing under the Medicare Physician Fee Schedule (MPFS) can report 93356 as a separately reimbursable service when paired with a primary echocardiography code and supported by appropriate documentation. The actual payment amount varies by geographic locality and changes annually. Use the CMS Physician Fee Schedule lookup tool to find current Relative Value Units (RVUs) and calculated payment rates for your MAC jurisdiction. Citing specific dollar figures without confirming the current year’s fee schedule is a common audit risk.

Facility Billing (Outpatient Hospital)

Medicare does not separately reimburse CPT 93356 when billed by outpatient hospitals. Because 93356 is an add-on code, CMS bundles its payment into the Ambulatory Payment Classification (APC) rate for the primary echocardiography code. Outpatient hospital billing departments should not expect a separate line-item payment for 93356 under Medicare. Commercial payers, however, may separately reimburse 93356 on the facility side depending on their coverage policy. Verify each commercial contract individually before billing.

Modifiers for CPT 93356

When the technical and professional components are split between a facility and an independent cardiologist, the appropriate modifiers apply:

• Modifier 26 (Professional Component): In practice, 93356 is typically billed as a single charge by the interpreting cardiologist rather than split between facility and physician via 26/TC. Some payer-specific guidance references 26/TC modifiers, but under Medicare’s facility setting the technical component is packaged into the primary echo’s APC payment and a separate TC claim does not yield separate reimbursement. The cardiologist provides interpretation only and the technical equipment is hospital-owned
• Modifier TC (Technical Component): Use when billing for equipment and staff costs only, without physician interpretation
• Modifier 59 (Distinct Procedural Service): Rarely appropriate for 93356 given its inherent add-on status. Only consider when documentation supports that 93356 was a distinct service, typically not required for this add-on code given its inherent add-on status

Using a structured medical forms workflow that links the echocardiography order to the billing encounter helps practices apply the correct modifier at submission rather than discovering the error at denial review.

Payer Coverage Policies and Denial Management

Commercial payer coverage for CPT Code 93356 is not uniform. Several major insurers have published medical policies with specific coverage criteria that go beyond Medicare’s requirements.

Blue Cross Blue Shield Kansas covers 93356 when the procedure is performed according to its published medical policy criteria, which include cardiomyopathy, heart failure, and chemotherapy cardiotoxicity monitoring as covered indications. General cardiac evaluation does not qualify.

Blue Shield of California has a coverage policy that addresses both 93356 and HCPCS Code C9762 (cardiac MRI morphology and function). These are distinct codes for distinct technologies; C9762 covers cardiac MRI with strain imaging (the ‘with strain imaging’ component is what creates coder confusion, since both codes involve strain analysis but derive it from different imaging modalities: echo vs MRI). C9762 covers cardiac MRI, not echocardiographic speckle tracking. Submitting the wrong code for the technology performed is a frequent billing error in academic cardiology practices.

Federal Employee Program (FEP) Blue follows its own Medical Policy Manual guidance on myocardial strain imaging with coverage criteria that may differ from commercial BCBS plans in non-FEP markets.

When a claim for CPT Code 93356 is denied, the most productive denial management steps follow this sequence:

1. Confirm the primary echocardiography code was included on the claim
2. Review the procedure report for all five required documentation elements
3. Verify the ICD-10 diagnosis code matches the payer’s covered indications list
4. Check whether the payer requires prior authorization for myocardial strain imaging
5. Review the payer’s specific medical policy for 93356 before submitting a peer-to-peer or appeal

When prior authorization is required, an Advance Beneficiary Notice (ABN) should be issued when Medicare coverage is uncertain for a specific patient scenario. The Office of Inspector General (OIG) identifies echocardiography coding as a documented area of billing scrutiny, so consistent documentation practices across all 93356 claims support compliance. Practices using integrated medical practice management software can track denial patterns by payer and identify recurring documentation gaps that drive appeal volume.

Expert Picks

Looking for a complete echocardiography billing workflow? Claims Management Software outlines how Pabau helps practices configure code pairing rules and reduce denials for complex cardiology billing.

Need guidance on structuring clinical documentation for compliance? HIPAA Compliance for Medical Offices covers documentation standards that apply to echocardiography and specialty procedure billing.

Managing billing across multiple providers or locations? Best Medical Practice Management Software reviews platforms that support multi-provider cardiology billing workflows.

Conclusion

CPT Code 93356 gives cardiology practices a compliant pathway to bill for speckle tracking echocardiography, but the add-on code framework, documentation requirements, and payer-specific coverage policies create multiple points of failure if billing workflows are not properly structured.

Pabau’s claims management software helps cardiology and multispecialty practices configure add-on code pairing rules, flag incomplete documentation before submission, and track denial patterns across Medicare and commercial payers. To see how Pabau supports echocardiography billing workflows, book a demo with the team.

Frequently Asked Questions