CTA Medical Necessity and Documentation Requirements: A New Audit Focus


When it comes to coding and billing for CTA, the codes have (for the most part) been around for a while, but that doesn’t mean challenges don’t exist. Issues with documentation and medical necessity are common risk areas from a coding and reimbursement perspective – especially pertaining to studies of the chest. Understanding the differences between CT vs. CTA, what’s required to code for CTA and what to look for in documentation can help clarify gray areas and reduce the risk of over-coding and under-coding while avoiding unwanted auditor attention.


As stated above, these are known, common challenges and no changes have come out (or are anticipated at this point) when coding for these services – so why the review? In July 2019, the Centers for Medicare and Medicaid Services (CMS) Recovery Audit program approved a complex, outpatient review of medical necessity and documentation requirements for computed tomography coronary angiography; specifically, CPT® code 75574.


Computed tomographic angiography, heart, coronary arteries and bypass grafts (when present), with contrast material, including 3D image post-processing (including evaluation of cardiac structure and morphology, assessment of cardiac function, and evaluation of venous structures, if performed)

The details of the approved audit topic from CMS can be found HERE


Since this is a complex review, recovery auditors will be requesting claims data from providers for review vs. an automated review, where no records are requested or sent, and the review is completed solely through data analysis. Claims can be requested as far back as three years.

CT scans take cross-sectional images of soft tissues or skeletal anatomy. CTA takes the CT scan a step further by creating cross-sectional images of soft tissues, skeletal anatomy and vascular structures. After the scan is complete, computer post-processing is used to create 3D images. This 3D post-processing is the key distinction between a standard CT and a CTA.

This means that now is the time to revisit and solidify your understanding of documentation requirements when it comes to coding for a CTA vs. a standard CT.

The imaging of the vessels alone is not necessarily considered a CTA for coding purposes. To report a CTA code, 3D post-processing must be done to evaluate the vessels – if there is no 3D reformatting performed to evaluate the vessels, then the exam should be coded as a CT and not a CTA. If the details in the documentation are unclear as to whether the exam should be coded as a CTA vs. a CT, it’s always best to request clarification – even though a physician may identify a procedure as a CTA, that’s not always the case from a coding perspective. Code selections should be made based on the services provided and detailed in the documentation.

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