How to fix a denial caused by a billing or coding error

An Explanation of Benefits, or EOB, comes from your plan. It isn't a bill. It shows what the provider charged, the plan's allowed amount, what the plan paid and what you owe. Find the denied line, then look for the codes next to it.

Plans use two standard code sets published by X12, a standards body for electronic claims:

• Claim adjustment reason codes describe why a claim or service line was paid differently than it was billed. They often carry a two-letter prefix, such as PR for patient responsibility or CO for contractual obligation.
• Remittance advice remark codes give more explanation for an adjustment already described by a reason code.

CMS says a remark code is a note from the health plan, and the EOB usually explains each code at the bottom. Reason codes whose official descriptions point to paperwork include:

• 16: claim lacks information or has submission or billing errors.
• 4: the procedure code is inconsistent with the modifier used.
• 11: the diagnosis is inconsistent with the procedure.
• 18: exact duplicate claim or service.
• 22: care may be covered by another payer under coordination of benefits.
• 27: expenses incurred after coverage ended.
• 29: the time limit for filing has expired.
• 31: patient cannot be identified as the plan's insured.

In employer and individual plans, the denial must include the denial code and its meaning, and the plan must give you the diagnosis and treatment codes and their meanings on request.

• Wrong or mismatched codes. The procedure code, diagnosis code or modifier does not match the care, or one another. The provider's billing office fixes this with a corrected claim.
• Member information. A wrong member ID, misspelled name, wrong date of birth or old group number. Send the billing office a copy of your current insurance card.
• Coordination of benefits. If you have more than one plan, the primary payer pays first, up to its limits, and the secondary payer pays only costs the primary didn't cover. A code 22 denial means the plan thinks another plan should pay first. Call the plan to update your other-coverage information, and tell each provider about any changes in your coverage.
• Coverage dates. The service date falls outside your coverage period, or the plan has old enrollment data. Check with the plan or your HR office.
• Duplicates. The same service was billed twice, or a real second visit was flagged as a duplicate. CMS notes that double billing is especially common when you saw more than one provider.
• Late filing. Providers have deadlines for submitting claims. In Original Medicare, a claim must be filed no later than 1 calendar year after the date of service. Private plans set their own limits. If the provider missed the deadline, ask the billing office whether its contract with your plan lets it bill you for that amount.

CMS suggests asking the provider's billing department for a detailed bill: a list of the costs for each item or service. Then get a copy of your medical records and compare. You shouldn't get a bill for anything that isn't documented in your records. Some providers charge a fee for records, so ask first.

Line up three documents: the itemized bill, the EOB and your records. Your bill should not be higher than the patient balance on the EOB; if it is, talk to the provider.

Call the provider's billing office with the EOB in hand. Give the claim number, date of service and denial code, and ask them to:

• Confirm what went wrong.
• Send a corrected claim, and tell you the date it went out.
• Hold your account from collections while the claim is reprocessed.

Call the plan a week or two later to confirm the corrected claim arrived. Your insurer may be able to fix billing errors with the provider directly. Keep notes and dates from every phone call, including the name of the person you spoke with.

In Original Medicare, clerical errors, including minor errors and omissions, are handled as reopenings instead of appeals, so the provider asks the Medicare contractor to reopen the claim.

A corrected claim fits when the provider made the mistake. File an appeal yourself when:

• The provider will not resubmit, or keeps failing to, and the appeal deadline is getting close.
• The claim was right and the plan processed it wrong, such as applying the wrong benefit, network status or cost-sharing.
• The plan calls it paperwork, but the real dispute is about coverage or medical necessity.
• The corrected claim was denied for the same reason.

In Original Medicare, if the contractor disagrees that the issue is a clerical error, it must dismiss the reopening request and tell you your appeal rights. Deadlines vary by plan type; see the pages for employer plans, Marketplace plans, Medicare Advantage, Original Medicare and Medicaid. Consumer Assistance Programs may be able to help with billing issues if you get stuck.