The definitions for routine ECG codes 93010-93015 state “at least 12 leads.” So you have to make an extra effort to remember that CPT® also offers Category III codes for ECGs of 64 leads or more.
These Cat. III codes are related to body surface mapping (BSM), which is considered investigational (and therefore not payable) by many payers. The code for interpretation of a 64+ lead ECG is 0180T (Electrocardiogram, 64 leads or greater, with graphic presentation and analysis; interpretation and report only).
Keep in mind: The CPT® 2013 manual, as originally published, stated 93799 (Unlisted cardiovascular service or procedure) was appropriate for 64+ lead ECG. The AMA corrected this to instead point you to 0178T-0180T for these services. Remember that when a Cat. III code is available for a service, you must use the Cat. III code and not an unlisted Cat. I code. The correction document, “Errata and Technical Corrections in CPT® 2013,” is online at www.ama-assn.org/ama/pub/physician-resources/solutions-managing-your-practice/coding-billing-insurance/cpt/about-cpt/errata.page