Radiology coding errors are mistakes in CPT, HCPCS, or ICD-10-CM codes and modifiers that don’t match the imaging service performed or documented. The most common are wrong contrast codes, modifier 26/TC misuse, unsupported diagnoses, missing prior authorization, and bundling mistakes. Each can cause a denial, an underpayment, or an audit. Here are 10 errors to avoid and how to fix them.
What Are Radiology Coding Errors?
Radiology billing is more complex than most specialties. Claims are often split into technical and professional components, depend on contrast use and laterality, and face strict payer edits. A small mismatch between the report and the claim is enough to trigger a denial.
10 Common Radiology Coding Errors and How to Fix Them
1. Wrong or Outdated CPT Codes
Choosing a code that doesn’t match the modality, body part, or number of views. For example, knee X-rays are 73560 (1–2 views), 73562 (3 views), and 73564 (4+ views). Fix: code from the signed report and update code sets every January.
2. Incorrect Contrast Coding
An MRI of the brain is 70551 (without contrast), 70552 (with contrast), or 70553 (without, then with contrast). The wrong choice causes denials or underpayment, and contrast supply codes are often missed.
Fix: confirm contrast use in the report before coding.
3. Misusing Modifier 26 and TC
Modifier 26 is the professional (interpretation) component, and TC is the technical component. Billing global when you own only one part, or reversing them, commonly leads to CO-4 denials.
Fix: confirm who owns the equipment and who reads the study.
4. Other Modifier Errors
Modifier 59 is often overused, and modifiers such as 76 (repeat by same physician), 77 (repeat by another physician), 50, RT, and LT are often missed. Fix: apply modifiers only when documentation and payer rules support them.
5. Diagnosis Codes That Don’t Support Medical Necessity
Nonspecific ICD-10-CM codes, or symptoms that don’t meet payer criteria, lead to CO-50 denials. Fix: code to the highest specificity using the order and clinical indication.
6. Missing or Expired Prior Authorization
Many payers require authorization for MRI, CT, and PET. Claims without a valid approval, or outside the approved dates, are commonly denied with CO-197. Fix: verify authorization before scheduling and track expiry dates.
7. Bundling and Unbundling Errors
Billing separately what NCCI edits bundle together, such as imaging guidance already included in a procedure code, triggers CO-97 denials. Fix: run NCCI and MUE edits before submission.
8. Documentation Gaps
Missing orders, unsigned reports, absent laterality, or no clinical indication make claims hard to defend. Fix: require a signed order and a complete report before billing.
9. Duplicate Claims and Unflagged Repeat Studies
Resubmitting a claim without changes, or billing a repeat study without the right modifier, leads to CO-18 duplicate denials. Fix: check claim history before resubmitting.
10. Eligibility, COB, and Timely Filing Errors
Wrong payer order, inactive coverage, or late submission (CO-29) are administrative errors that cost as much as coding errors. Fix: verify eligibility and benefits at scheduling and track filing deadlines.
Example: CT With Contrast Coded as Without
A report documents a CT of the abdomen and pelvis with contrast. The coder submits 74176 (without contrast) instead of 74177 (with contrast). The claim is denied or underpaid because the code doesn’t match the report. A pre-bill check comparing the report and the code would have caught it.
How to Fix a Denied Radiology Claim
- Read the CARC/RARC denial codes on the remittance.
- Pull the order and the signed report.
- Compare CPT, modifiers, and ICD-10-CM codes to the report.
- Correct and resubmit, or appeal with supporting documentation.
- Track filing deadlines.
- Log the root cause to prevent repeats.
Radiology Coding Error Prevention Checklist
- Scrub claims before submission
- Check NCCI and MUE edits
- Match the order, report, and claim
- Track authorizations
- Update code sets every year
- Audit coded claims regularly
- Monitor denial rate and clean claim rate
Reduce Radiology Coding Errors With Expert Support
If the same denials keep repeating, a coding audit shows where the errors start. Our radiology billing services, medical coding services, and denial management help imaging providers submit cleaner claims. Get a free billing audit.
Frequently Asked Questions
What are the most common radiology coding errors?
Wrong CPT codes, contrast mismatches, modifier 26/TC misuse, unsupported diagnosis codes, missing prior authorization, and bundling errors are the most common.
What is the difference between modifier 26 and TC?
Modifier 26 reports the professional component, the radiologist’s interpretation. Modifier TC reports the technical component, covering equipment, supplies, and the technologist. If one provider does both, bill globally with no modifier.
Why are radiology claims denied for medical necessity?
Payers deny when the diagnosis or clinical indication doesn’t support the imaging ordered. Specific ICD-10-CM codes and a documented order reduce these denials.
Does radiology need prior authorization?
Many payers require it for advanced imaging like MRI, CT, and PET. Requirements vary by payer and plan, so verify before scheduling.
What is bundling in radiology billing?
Bundling means certain services are included in another code’s payment under NCCI edits. Billing them separately is unbundling and often causes denials.
How can practices reduce radiology coding errors?
Use claim scrubbing, NCCI checks, regular coding audits, and updated code sets, and match each claim to the signed report.
Sources: CMS NCCI edits, CMS Physician Fee Schedule (PC/TC indicators), AMA CPT, X12 CARC list.