TC/26 Split Billing in Cardiology: Modifier Errors That Cost Real Money

Mukesh MakwanaFounder & CEO · Hands-on medical billing & RCM across 11 specialties

A single incorrect modifier on a cardiology diagnostic test is one of the most common, and most preventable, denial causes in the specialty, and it happens because the TC/26 split is more specific than most billers realize.

What TC and 26 actually split

Many cardiology diagnostic tests, echocardiograms, stress echoes, nuclear studies, separate into two billable components: the technical component (TC), covering the equipment and staff performing the test, and the professional component (26), covering the physician's interpretation. Whoever owns the equipment bills TC. Whoever interprets the study bills 26. Bill both when only one applies, or bill the wrong one, and the claim gets denied.

Where this actually breaks in practice

The error usually isn't ignorance of the modifier, it's ambiguity about equipment ownership in shared or leased-equipment arrangements, or a physician interpreting a study performed at a facility they don't own. If your billing team isn't verifying equipment ownership per location before assigning TC/26, this is where denials originate.

Cath lab and EP billing carry their own version of this problem

Interventional cardiology and electrophysiology procedures add another layer: multiple providers, multiple facilities, and device-related billing that has to be reconciled against the actual procedure performed. The same principle applies, documentation has to match exactly who did what, where. Diagnostic catheterization such as CPT 93458 splits into TC and 26 like an echo. Interventional and ablation codes such as CPT 92928 and CPT 93656 do not: the 2026 CMS relative value file gives them a PC/TC indicator of 0, so they are billed without either modifier in every setting.

Why this needs cardiology-specific claim logic

A general medical billing process treats modifiers as a single universal rule set. Cardiology's TC/26 usage is dense enough, and varies enough by procedure type, that it needs to be checked against the specific test and ownership structure every time. Our cardiology billing page covers the fuller set of denial patterns we watch for.

Code guides: which codes split, and how

Each guide shows the 2026 Medicare RVUs for the global, 26 and TC lines, taken from the CMS relative value file.

• CPT 93306. Complete TTE: splits into 26 and TC.
• CPT 93350. Stress echo: splits into 26 and TC.
• CPT 78452. Myocardial perfusion SPECT: splits into 26 and TC.
• CPT 93458. Left heart cath with coronary angiography: splits into 26 and TC.
• CPT 93297. Implantable monitor remote evaluation: 26 and TC for Medicare.
• CPT 93000. ECG: splits through separate codes 93005 and 93010, not modifiers.
• CPT 93015. Stress test: splits through 93016, 93017 and 93018, not modifiers.

Sources

Centers for Medicare & Medicaid Services, Physician Fee Schedule, cms.gov.
American College of Cardiology, acc.org.