Forty-eight hours, seven days, fifteen days or thirty days: for ambulatory heart monitoring, wear time picks the code. The Holter monitor CPT code family, 93224 to 93227, covers recordings up to 48 hours. Extended ECG patches move to 93241 to 93248, split at seven days, and mobile cardiac telemetry bills 93228 and 93229 for up to 30 days.
Within each family, separate codes cover the global service, the hookup, the scanning report and the physician interpretation. So ambulatory ECG billing comes down to two questions: how long the patient wore the device, and which part of the work each provider performed.
Choose the Holter Monitor CPT Code by Wear Time
Start with the recording length in the report, not the device name on the order. Then climb the ladder until the duration fits.
Up to 48 hours: a traditional Holter, coded 93224 to 93227. Most 24-hour and 48-hour studies land here.
More than 48 hours, up to 7 days: an extended ECG patch, coded 93241 to 93244.
More than 7 days, up to 15 days: a longer patch study, coded 93245 to 93248, such as the 93248 15-day patch interpretation.
Up to 30 days, recorded only around events: an event monitor, coded 93268 to 93272.
Up to 30 days, transmitted in real time: mobile cardiac telemetry, coded 93228 and 93229.
As a result, the same patch device can fall into two different code ranges depending on how many days the patient actually wore it. So bill from the report’s recorded hours, and never from the planned duration.
Holter and Extended ECG Codes, Component by Component
Both families split the service into the same four parts. Once the duration is set, the only question is which part each provider performed.
| Component | Holter, up to 48 hours | Extended ECG, over 48 hours to 7 days / over 7 to 15 days |
|---|---|---|
| Global (all parts) | 93224 | 93241 / 93245 |
| Recording: hookup, recording, disconnection | 93225 | 93242 / 93246 |
| Scanning analysis with report | 93226 | 93243 / 93247 |
| Physician review and interpretation | 93227 | 93244 / 93248 |
Holter: 93224 to 93227
As Aetna’s policy describes, 93224 is external ECG monitoring for up to 48 hours with continuous recording and storage. In other words, the 93224 Holter 48 hours code covers the whole service when one provider owns the device and reads the study. For example, a cardiology practice that places the monitor and reads it in-house bills 93224 alone. In contrast, the 93227 Holter interpretation code applies when the physician only reads a study recorded and scanned elsewhere.
Extended ECG: 93241 to 93248
The 93241 extended ECG monitoring code and its partners replaced the older Category III codes for patches. They follow the same four-part logic but split at seven days. So a 10-day patch read by the ordering cardiologist bills 93248 for the interpretation, while the patch vendor or testing facility bills 93246 and 93247.
Holter vs Event Monitor vs Mobile Telemetry
The three device types answer different clinical questions, so they also bill differently.
Holter and extended patch: records every heartbeat continuously, then a technician scans the full recording after the device comes off. Best for frequent symptoms or arrhythmia burden.
Event monitor: records only around symptoms or triggered events for up to 30 days. Event monitor CPT 93268 is the global code, with 93270 for recording, 93271 for transmission and analysis, and 93272 for the physician review.
Mobile cardiac telemetry: streams data to a monitoring center in near real time for up to 30 days, so staff can act during the event. Mobile cardiac telemetry 93228 93229 billing splits the work: 93229 is the technical monitoring service, and 93228 is the physician review and report.
In addition, Noridian notes that each family must be billed as a set, and a set cannot be repeated within 29 days. Overlapping claims from two providers deny, often without appeal rights, so confirm what the ordering physician actually ordered. Implanted loop recorders follow different rules, covered in our guide to device interrogation CPT codes.
Who Bills What, and Why
Holter monitor reimbursement depends on two things beyond the code: which provider performed which part, and whether the diagnosis supports the test.
Component Codes, Not Modifiers
Many coders reach for a Holter modifier 26 TC split, as they would for an echocardiogram. However, every family above already has its own component codes. So the reading physician bills 93227, 93244 or 93248, and the facility or vendor bills the recording and scanning codes, with no 26 or TC appended. Only the provider who performs every part bills the global code.
Diagnoses That Support the Study
Payers expect a symptom or condition that explains why monitoring is needed. For example, Aetna’s policy lists palpitations (R00.2), syncope (R55), dizziness (R42) and atrial fibrillation (I48.0 to I48.92) among covered diagnoses, and it generally limits Holter studies to twice in six months. Our cardiology billing cheat sheet lists related cardiac codes for quick reference.
Five Denials and How to Prevent Them
Many ambulatory ECG denials trace back to a mismatch between the claim and the report. Each one below has a simple prevention step.
- Wrong duration range. A 52-hour study billed as a Holter denies, because anything over 48 hours belongs in 93241 to 93248. Prevention: code from the recorded hours on the report.
- Global billed by two providers. When the vendor bills 93245 and the cardiologist also bills it, one claim denies as a duplicate. Prevention: agree in advance who bills global and who bills components.
- Overlapping studies. A second set within 29 days of the first denies under overlap edits. Prevention: check the patient’s recent monitoring before scheduling.
- Unsupported diagnosis. A routine screening code without symptoms rarely supports the study. Prevention: report the symptom or arrhythmia that prompted the order.
- Modifiers on component codes. Adding 26 to 93227 or 93248 causes edits to fail. Prevention: bill the matching component code alone.
Our post on cardiac diagnostic billing covers the wider testing workflow, and our cardiology coding guidelines explain documentation basics.
Holter, Patch or MCT, Each Study Can Pay in Full
Every Holter monitor CPT code decision follows the same two steps. First, the recorded wear time picks the family: Holter up to 48 hours, extended ECG to 7 or 15 days, or event and telemetry monitoring up to 30 days. Then the work each provider performed picks the global or component code, without 26 or TC.
Practices, hospitals and testing facilities that share these studies need clear agreements on who bills each part. MBW RCM can set up those billing rules with each partner and check every monitoring claim against the report, and its cardiology billing services handle the follow-up when a study is denied.
Holter Monitor CPT Code FAQs
What is the CPT code for a 24-hour Holter monitor?
Use 93224 when one provider performs the whole service. Otherwise, split it into 93225 for recording, 93226 for scanning and 93227 for the physician’s interpretation.
Which code applies to a 14-day patch monitor?
A study over 7 days and up to 15 days uses 93245 for the global service, or 93246, 93247 and 93248 for the components.
Can modifier 26 be added to 93224?
No. The Holter family has its own component codes, so the physician bills 93227 for the interpretation instead of 93224-26.
What is the difference between an event monitor and MCT?
An event monitor records only around symptoms or triggers, billed with 93268 to 93272. In contrast, mobile cardiac telemetry transmits data in near real time and bills 93228 and 93229.
How often can a Holter monitor be billed?
Medicare contractors deny a repeat set within 29 days, and some commercial plans, such as Aetna, generally limit Holter studies to twice in six months.