American College of Physicians: Internal Medicine — Doctors for Adults ®


Tips to help you avoid making common billing mistakes

From the November ACP-ASIM Observer, copyright © 2002 by the American College of Physicians-American Society of Internal Medicine.

By Angela Pledger

Top 10 Medicare billing errors

Q: Where can I find a list of the most common Medicare billing errors?

A: A list of the 10 most common physician billing errors is on the Web site of Medicare's Maryland carrier. (Look for Provider Reports and click on "Top 10 Billing Errors.") The site contains a description of the errors as well as instructions to resolve them.

The top three billing errors on the list involve a failure to complete verification and cross-reference information to ensure accuracy; failure to file under certain time limits; and failure to enter information in appropriate fields.

Medicare hopes the list will help physicians minimize claims-processing errors and help them resubmit denied claims. The Maryland Medicare carrier identified the 10 billing errors through analysis of its claims data and provides quarterly updates.

Q: What type of information does the list provide?

A: The list provides the billing error, the reason the claim is incorrect and some ways to correct the problem. You can use the resolution section as a checklist to make sure the information you provide on claims is accurate.

Here is a summary of the three most frequent Medicare billing errors—and some solutions—listed on the Maryland Medicare carrier's Web site.

Beneficiary information


Providers fail to provide the accurate Medicare beneficiary's name, health insurance claim (HIC) number or sex. In some cases, the beneficiary's name is misspelled or does not match the eligibility file, the HIC number is incorrect or incomplete, or the beneficiary's gender is incorrect or missing.


  • Verify beneficiaries' name, HIC number and sex using their Medicare card.
  • Enter beneficiaries' first and last name in block two of the HCFA 1500 form. If you're submitting claims electronically, use field CA0-04.0 (patient last name) and CA0-05.0 (patient first name) on the National Standard Format field mappings.
  • Enter the HIC number in block 1a of the HCFA 1500 form (field Dao-18.0 for electronic claims). The nine characters must be numeric. The 10th character must be alphabetic (no space). The 11th and 12th characters must be alpha-numeric (no spaces).
  • Enter the beneficiary's sex in block three of the HCFA 1500 form (field CA0.09.0 for electronic claims). Use only F or M.

Group/practice number


Providers fail to use the correct group number/provider identification number (PIN) assigned by the Medicare carrier.


  • Verify the group/PIN number.
  • Enter the group/PIN number in block 33 of the HCFA 1500 form (field BA0-09.0 for electronic claims).

Diagnosis codes


ICD-9-CM diagnosis codes are incorrect, missing or invalid.


  • Verify the ICD-9-CM diagnosis code.
  • Enter the ICD-9-CM code number to the highest level of specificity (code to the fourth or fifth digit) in block 21 of the HCFA 1500 form. For electronic claims, use field EAO-32.0 for DX code 1, EAO-33.0 for DV code 2, EAO-34.0 for DX code 3 and EAO-35.0 for DX code 4.

Angela Pledger is Coordinator for Regulatory and Insurer Affairs in the College's Washington office.


Top 10 Medicare billing errors

According to the Medicare carrier for Maryland, the following 10 areas give physicians the most trouble when it comes to submitting claims for services.

  1. Beneficiary information
  2. Group/practice number
  3. Diagnosis codes
  4. Late claims
  5. Modifiers
  6. Provider number
  7. Place of service
  8. Procedure codes
  9. Quantity of services
  10. Unique physician identification number


This is a printer-friendly version of this page

Print this page  |  Close the preview




Internist Archives Quick Links

Fenway Guide to Lesbian, Gay, Bisexual, and Transgender Health, 2nd Edition

Fenway Guide to Lesbian, Gay, Bisexual, and Transgender Health, 2nd Edition This new edition reflects recent clinical and social changes and continues to present the important issues facing practitioners and their LGBT patients. Read more about the Guide. Also see ACP’s recent policy position paper on LGBT health disparities.

Join Us in Washington, DC for the Most Comprehensive Meeting in Internal Medicine

Join Us in Washington, DC for the Most Comprehensive Meeting in Internal Medicine
Register now and enjoy:

Discounted rates, the best national faculty, a wealth of clinical and practice management topics and hands-on sessions! Learn more about the meeting.