CMS Heartsbreath Test Coverage Policy: What Billing Teams Need to Know About NCD 325

CMS has issued a modification to National Coverage Determination (NCD) 325, governing the Heartsbreath test for heart transplant rejection detection. While the underlying non-coverage determination dates back to December 2008, this policy update keeps the record current for Medicare billing purposes. If your organization bills for post-transplant diagnostic services, understanding this NCD is essential to avoiding claim denials.

What Is the CMS Heartsbreath Test Policy Under NCD 325?

The Centers for Medicare & Medicaid Services — the federal agency that administers Medicare — has maintained a non-coverage position on the Heartsbreath test since December 8, 2008, and this modified NCD 325 reaffirms that stance. The Heartsbreath test is a Food and Drug Administration-approved Humanitarian Use Device designed to detect Grade 3 heart transplant rejection. It works as an adjunct to the endomyocardial biopsy — not a replacement for it.

The device is narrowly indicated even outside of Medicare: it applies only to patients who have had a heart transplant within the last year and have undergone an endomyocardial biopsy within the prior month. The test involves collecting breath samples from the patient, analyzing those samples in a laboratory setting, and comparing the results to biopsy findings for the treating clinician.

Despite its FDA humanitarian use designation, CMS determined that the evidence does not adequately define the technical characteristics of the test nor demonstrate that it improves health outcomes in Medicare beneficiaries. That's the critical phrase driving non-coverage — the standard under section 1862(a)(1)(A) of the Social Security Act requires services to be "reasonable and necessary," and CMS concluded the Heartsbreath test does not meet that bar.

Why CMS Determined the Heartsbreath Test Is Not Covered

CMS's non-coverage rationale rests on two distinct evidentiary gaps, both of which remain unresolved in this updated NCD:

1. Undefined technical characteristics — CMS found that the body of evidence did not adequately establish the technical performance parameters of the test itself.
2. No demonstrated health outcome improvement — Even as an adjunct to biopsy, the test did not show evidence of improving outcomes for Medicare beneficiaries in the transplant population.

It's worth noting that the FDA's Humanitarian Use Device designation means the device is approved for use in a rare condition (affecting fewer than 8,000 patients annually in the U.S.), but FDA approval and CMS coverage are entirely separate determinations. FDA clearance does not guarantee Medicare reimbursement — and this policy is a clear example of that distinction in practice.

The non-coverage applies broadly: there are no nationally covered indications listed under NCD 325. The policy does not identify any patient subgroup, clinical scenario, or documentation threshold that would qualify a claim for Medicare payment.

Clinical Context: Where the Heartsbreath Test Fits in Transplant Care

For transplant programs and cardiology billing teams, it helps to understand where this test sits in the clinical workflow. Post-heart transplant rejection monitoring is a high-stakes process. The endomyocardial biopsy is the gold standard for rejection surveillance, but it's an invasive procedure. The Heartsbreath test was developed to serve as a noninvasive adjunct — analyzing volatile organic compounds in exhaled breath as potential biomarkers of Grade 3 (severe) rejection.

The one-year post-transplant window and the requirement for a biopsy within the prior month as conditions of use signal that this was designed for a very specific, high-acuity monitoring scenario. Despite the clinical rationale for reducing invasive procedures in transplant patients, CMS's evidentiary standard was not satisfied at the time of the original determination — and nothing in this NCD modification changes that conclusion.

Affected Codes Under CMS NCD 325

The policy data for NCD 325 does not list specific CPT or HCPCS codes associated with the Heartsbreath test. No covered or non-covered procedure codes are enumerated within this NCD.

For billing teams seeking to identify any claims that may have been submitted for this service, it is recommended to work with your coding team to search internal claim history using any laboratory or breath analysis codes that may have been applied historically. Consult the claims processing transmittals referenced in the policy — TN 1683 and TN 1697 (Medicare Claims Processing) — for any coding guidance CMS issued at the time of the original 2008 determination.

Because no codes are specified in the current NCD, billing teams should not attempt to map this policy to existing CPT codes without direct guidance from CMS or a qualified coding consultant.

What Your Billing Team Should Do