If more of your claims are coming back unpaid this year, you are not imagining it. Medical claims are being denied in 2026 mainly because of front-end mistakes such as wrong patient or insurance details, missing prior authorizations, thin documentation, coding and modifier errors, and payers who now check claims with stricter automated rules. Most of these causes can be prevented, and many denied claims can still be paid if you correct or appeal them on time.
| Quick answer The most common reasons claims are denied in 2026 are: eligibility and registration errors, missing or invalid prior authorization, medical necessity that the note does not support, coding and modifier errors, bundling edits, missing claim information, duplicate submissions, late filing, coordination of benefits mistakes, and provider enrollment gaps.The fix is the same in every case. Catch the problem before the claim goes out, read the denial code carefully when one comes back, and appeal inside the payer’s deadline. |
This guide explains each cause in simple terms, shows what the codes on your remittance advice mean, and gives you a simple workflow to prevent denials and recover the ones you already have.
What Is a Claim Denial?
A claim denial happens when a payer processes your claim and decides not to pay all or part of it. The payer explains why on the remittance advice (called an ERA when electronic, or an EOB on paper) using standard codes. Knowing the exact type of denial tells you what to do next, so it is worth getting the terms straight.
Denial vs. rejection
A rejection is not the same as a denial. A rejected claim never entered the payer’s system because of a data or format problem, such as a missing field or an invalid ID. Your clearinghouse or the payer usually catches it within a day or two. Because the claim was never processed, there is nothing to appeal. You fix the error and send it again.
A denial means the claim was processed and refused. You must either correct and resubmit/reprocess it or file an appeal, depending on the reason.
Soft denials and hard denials
A soft denial is temporary and fixable, for example a missing modifier or a missing authorization number that you can supply. A hard denial will not be paid unless you win an appeal, for example a service the plan does not cover or a claim sent after the filing deadline. Working soft denials fast is where most practices recover the most money.
How to read denial codes
Every denial comes with a Claim Adjustment Reason Code (CARC). Many also carry a Remittance Advice Remark Code (RARC) that adds detail, and a group code that shows who is responsible for the unpaid amount. CO (contractual obligation) means the practice generally cannot bill the patient for it. PR (patient responsibility) means the amount can move to the patient. OA (other adjustment) and PI (payer-initiated reduction) are also used.
| Code | What it usually means | First thing to check |
| CO-4 | Procedure code does not match the modifier, or a required modifier is missing | Modifier on the claim vs. the note |
| CO-11 | Diagnosis does not fit the procedure | Diagnosis pointers and code specificity |
| CO-16 | Claim lacks information or has a billing error | The RARC, which names the missing item |
| CO-18 | Exact duplicate claim or service | Claim status before you resubmit |
| CO-22 | May be covered by another payer (coordination of benefits) | Primary and secondary order |
| CO-27 | Service happened after coverage ended | Eligibility on the date of service |
| CO-29 | Filing time limit has expired | Proof of timely filing |
| CO-50 | Payer does not see the service as medically necessary | Documentation and payer policy |
| CO-97 | Payment is included in another service (bundled) | NCCI edits and modifier use |
| CO-109 | Claim belongs to a different payer | Payer and plan on the patient’s card |
| CO-197 | Authorization or notification is missing | Authorization number, dates, and units |
| NotePayers sometimes use these codes in slightly different ways. Always read the RARC and the payer’s own explanation before you decide how to respond. |
How Common Are Claim Denials in 2026?
No single number fits every practice, because studies measure different groups. Benchmark reviews that cite MGMA data put first-submission denials for physician practices at roughly 7% to 8% in recent years. The American Academy of Family Physicians describes 5% to 10% as a typical range and treats a rate under 5% as the better goal. Hospital and payer-side figures often run higher, so be careful when you compare your own rate to a number you see in a headline.
The direction matters more than any one figure, and the direction is not good. An MGMA Stat poll found that 60% of medical group leaders saw their denial rates go up, while only 11% had managed to bring them down. An Experian Health survey of 250 health care professionals found that 41% of providers now report denial rates above 10%, up from 30% three years earlier.
Prior authorization is a big part of the pressure. The American Medical Association’s 2025 physician survey, published in 2026, found that practices complete an average of 40 prior authorizations per physician each week and spend about 13 hours of physician and staff time on them. Nearly one in three physicians (32%) said these requests are often or always denied, and 40% said they have staff who work only on prior authorization.
| Why this matters Every denial costs you twice. You lose time while the payment is held, and your staff spends more time reworking the claim than it would have taken to send it clean. A small rise in your denial rate adds up quickly over a year. |
| Note Your own denial rate is the number that counts. Divide the claims denied on first submission by all claims submitted in the same period, then track it every month. You can also measure it by dollars, which shows whether high-value claims are denied more often than low-value ones. |
Why Are Claim Denials Rising in 2026?
Four shifts explain most of what practices are seeing this year.
Payers are checking claims with more automation
Many payers run claims through automated edits and software tools before a person looks at them. In the AMA’s survey, 61% of physicians said they worry that insurer use of artificial intelligence is raising prior authorization denial rates. Automated review is strict by design. A missing diagnosis, a modifier that does not match, or a short note that a human reviewer might have accepted can now trigger a denial on its own.
Prior authorization is heavier and stricter
KFF reported that Medicare Advantage insurers received nearly 53 million prior authorization requests and fully or partially denied 4.1 million of them, which is 7.7%. Practices also report denials for “no authorization” even when approval was given, usually because the authorization number, dates, units, or rendering provider on the claim do not match what the payer approved.
| Note: the 2026 CMS prior authorization ruleUnder the CMS Interoperability and Prior Authorization Final Rule (CMS-0057-F), Medicare Advantage plans, Medicaid and CHIP plans, and certain other government-regulated payers must send prior authorization decisions within 72 hours for urgent requests and 7 calendar days for standard requests, starting in 2026. They must also give a specific reason when they deny a request, and report prior authorization metrics publicly.Some limits apply. The rule does not cover drugs, it does not reach most employer-sponsored commercial plans, and the required electronic prior authorization systems come later, with most compliance dates in January 2027. It should make decisions faster and clearer, but it does not remove prior authorization requirements. |
Codes and payer policies keep changing during the year
The ICD-10-CM code set for fiscal year 2027 took effect on October 1, 2026 and applies to encounters through September 30, 2027. Each update adds, revises, and deletes codes. If your system still offers a code that was deleted, or a code that is now only a category header and needs more digits, the claim will be denied. The National Correct Coding Initiative (NCCI) bundling edits are also updated every quarter, and large commercial payers add their own bundling pairs on top of them.
Telehealth has been the most confusing area. Medicare telehealth flexibilities lapsed on October 1, 2025 during the government shutdown, and lapsed again briefly at the end of January 2026. The Consolidated Appropriations Act, 2026, signed on February 3, 2026, extended them through December 31, 2027. Because later extensions were applied retroactively, older telehealth denials from those gap windows are worth a second look. Also note that from October 1, 2026, rural health clinics and federally qualified health centers no longer bill non-behavioral distant-site telehealth with code G2025. They bill the specific CPT or HCPCS code with modifier 95 or 93.
Payers expect more from your documentation
Medical necessity rules, step therapy requirements, and prior authorization scope have all widened across major payers in recent years. A note that said “patient has back pain, MRI ordered” may have been paid before. Today the payer often wants the duration of symptoms, the exam findings, the treatments already tried, and the reason the test is needed now.
The Most Common Causes of Claim Denials and How to Fix Each One
Industry reviews agree that eligibility, authorization, and registration problems make up the largest share of denials. Physicians Practice has pointed out that the most common triggers, including incorrect demographics, missing insurance information, and absent preauthorizations, start at registration and not in the billing office. That is good news, because front-end problems are the cheapest ones to fix.
1. Eligibility and registration errors
Why does it happen? The patient’s coverage ended or changed, often in January. The member ID has a typo. The name or date of birth does not match the insurance card. The claim goes to the wrong payer or plan.
How to fix it. Verify eligibility when the visit is scheduled and again close to the visit date, using the payer portal or a real-time check through your clearinghouse. Scan the front and back of the insurance card at every visit, and ask each patient whether anything has changed since the last one. Enter names exactly as they appear on the card.
2. Missing or invalid prior authorization or referral
Why does it happen? The service needed approval and nobody requested it. Or approval exists but for a different code, date range, number of units, or provider than the one billed. Or it expired before the visit.
How to fix it. Keep a short list of the authorization rules for your top payers and your most common high-cost services, and update it often. Before the visit, confirm that the approved code, dates, units, and provider match the schedule. Put the authorization number in the correct field on the claim. If a claim is denied even though you had approval, appeal with a copy of the approval letter.
3. Medical necessity not supported
Why does it happen? The diagnosis on the claim does not meet the payer’s coverage policy for the service, or the note does not explain why the service was needed. Medicare uses national and local coverage determinations, and commercial payers publish their own medical policies.
How to fix it. Check the payer’s policy before ordering expensive tests or procedures. Train providers to record symptoms, how long they have lasted, exam findings, treatments already tried, and why the service is needed now. Link the most specific diagnosis to each procedure. For Medicare patients, use an Advance Beneficiary Notice (with the GA modifier) when you expect Medicare to deny a service as not medically necessary. For a denial that is already in, ask for a peer-to-peer review with the payer’s medical director.
4. Coding and modifier errors
Why does it happen? The E/M level is not supported by the note. An unspecified diagnosis code was used when a specific one was available. A code was deleted or changed in the latest update. A modifier is missing, wrong, or does not match the place of service.
How to fix it. Load new code sets on time, since ICD-10-CM changes every October 1 and CPT and HCPCS changes start January 1. Run every claim through a claim scrubber before it leaves your office. Code to the highest level of detail the record supports and nothing beyond it. Review a small sample of claims from each provider every month and share the results with them.
5. Bundling and NCCI edits
Why does it happen? Two services were billed together that the payer treats as one. Medicare’s NCCI edits list code pairs that normally cannot be paid together, and many commercial payers add their own pairs. Modifier 59 and the X modifiers are meant to show that two services were truly separate, and they are often added to force payment.
How to fix it. Check the NCCI procedure-to-procedure edit tables, which are updated quarterly, before you bill two services on the same day. Add a modifier only when the record shows a separate and distinct service, such as a different session, site, or encounter. Overuse of modifier 59 is a common audit focus, so the note must support every use. You can also consult reputable medical billing audit services if you are unsure how to do it yourself.
6. Missing or incorrect claim information
Why does it happen? The claim is missing a referring provider, taxonomy code, NPI, service date, or billing address, or one of them is wrong. These claims usually come back with CO-16. Many CO-16 denials come down to a wrong or missing data element, including how the billing, rendering, and referring parties are identified. Entity codes in medical billing explains how these are reported.
How to fix it. Read the RARC, which names the missing or wrong item, then correct it and resubmit. To stop it from happening again, build payer-specific claim templates and let your scrubber block claims with empty required fields.
7. Duplicate claims
Why does it happen? The same claim was sent twice, often because someone resubmitted before the first one finished processing. Billing a service in pieces can also look like a duplicate.
How to fix it. Check the claim status before you resend anything. When you are correcting a claim that was already processed, use the payer’s corrected claim process (a replacement claim with the right frequency code) and not a brand new claim.
8. Timely filing missed
Why does it happen? The claim reached the payer after the filing deadline. Original Medicare generally requires claims within one year of the date of service. Commercial payers set their own limits by contract, and some are far shorter than a year.
How to fix it. Write down the filing limit for each payer you bill. Review unbilled and unpaid claim reports every week. Keep the clearinghouse acceptance report as proof of the date you filed, because that proof is what wins a timely filing appeal.
9. Coordination of benefits mistakes
Why does it happen? The patient has more than one plan and the claim went to the wrong one first, or the patient never told you about other coverage. For Medicare patients, another payer may be primary.
How to fix it. Ask about other coverage at every visit. Complete the Medicare Secondary Payer questionnaire when it applies. When a payer sends coordination of benefits information, update the patient’s record the same day.
10. Provider enrollment and credentialing gaps
Why does it happen? A new provider started seeing patients before the payer approved their enrollment. A revalidation or CAQH attestation lapsed. The provider is out of network for that plan.
How to fix it. Start credentialing early, because it can take months. Track each provider’s effective date with each payer and do not schedule that payer’s patients with the provider until the date is confirmed. Keep revalidation and attestation dates on a shared calendar.
11. Telehealth billing errors
Why does it happen? The claim used place of service 11 (office) instead of 02 or 10. The modifier is missing or wrong. A code was used that the payer does not recognize. Medicare, for example, has not adopted the newer 98000-series telehealth codes, so Medicare telehealth visits are billed with the usual office E/M codes plus the right place of service and modifier.
How to fix it. Use place of service 10 when the patient is at home and 02 when the patient is anywhere else. Use modifier 95 for live audio and video and modifier 93 for audio-only, and check each commercial payer’s own rules, since they vary. Review your telehealth claim templates every quarter so old defaults do not carry forward.
Here is a quick summary you can share with your team.
| Cause | Typical code | Where it starts | First fix |
| Eligibility and registration | CO-27, CO-109 | Front desk | Verify coverage before each visit |
| Missing authorization | CO-197 | Scheduling | Match approval to the claim |
| Medical necessity | CO-50 | Clinical note | Document the reason and prior treatment |
| Coding and modifiers | CO-4, CO-11 | Coding | Update code sets and scrub claims |
| Bundling | CO-97 | Coding | Check NCCI edits before billing |
| Missing information | CO-16 | Registration and billing | Read the RARC and correct |
| Duplicates | CO-18 | Billing | Check status before resending |
| Late filing | CO-29 | Billing | Work unbilled reports weekly |
| Coordination of benefits | CO-22 | Front desk | Ask about other coverage |
| Enrollment gaps | Varies | Credentialing | Confirm effective dates first |
How to Prevent Claim Denials: A Simple Workflow
Preventing a denial is almost always cheaper than fixing one. The workflow below follows the claim from scheduling to payment, so each team member knows where they can stop a problem and how to prevent from a claim denial.
Before the visit
Confirm coverage and benefits, check whether the service needs prior authorization or a referral, and request it early. Collect complete and accurate demographics. Confirm that the provider is enrolled with the patient’s plan for the date of service.
During the visit
Make sure the note shows why the service was needed, what was found, and what was done. Record the details that support the E/M level and any modifiers. If a provider’s documentation is unclear, the coder should send a question to the provider before the claim is billed, not after it is denied.
Before you submit
Run the claim through a scrubber. Have a coder look at high-risk claims, such as high-cost procedures, claims with modifiers, and services that often need authorization. Confirm the authorization number is on the claim and that the diagnosis supports the procedure.
After you submit
Check claim status within about two weeks instead of waiting for the remittance. Work every denial within a few days of receiving it. Once a week, sort denials by reason, payer, and provider so you can see patterns, and meet monthly with front desk, clinical, and billing staff to fix the causes you find.
| Why this matters A denial that never happens costs nothing. A denial that is appealed costs staff time and delays payment, and the claim may still not be paid. The front desk and clinical team have as much control over your denial rate as the billing team does. |
What to Do When a Claim Is Denied
Work through the same steps every time, so nothing falls through the cracks.
- Read the group code, CARC, and RARC on the remittance advice, and read the payer’s letter if there is one.
- Decide what kind of denial it is. If something is missing or wrong, correct it and resubmit. If you believe the payer made the wrong decision, appeal. If the patient owes the amount (PR group code), bill the patient.
- Gather what you need: the clinical note, the authorization letter, the payer policy, proof of timely filing, or the corrected data.
- Send the corrected claim or appeal before the deadline, and keep proof that you sent it.
- Follow up on a set date. Do not wait for the payer to respond on its own.
- Record the root cause so the same denial does not return next month.
How to write a strong appeal
Keep it short, specific, and easy to check. Include the patient name, member ID, claim number, date of service, and the denial reason. Add one clear paragraph that explains why the denial is wrong and names the payer policy or guideline that supports payment. Attach the clinical notes and any other proof. State exactly what you are asking the payer to do. For medical necessity denials, ask for a peer-to-peer conversation with a physician reviewer as well.
Know your deadlines
For Original Medicare Part A and Part B, there are five levels of appeal, and each has its own time limit.
| Level | Who decides | Deadline to file |
| 1. Redetermination | Medicare Administrative Contractor | 120 days from receipt of the initial determination |
| 2. Reconsideration | Qualified Independent Contractor | 180 days from receipt of the redetermination |
| 3. Hearing | Administrative Law Judge | 60 days from receipt of the reconsideration |
| 4. Review | Medicare Appeals Council | 60 days from the judge’s decision |
| 5. Federal court | US District Court | 60 days from the Council’s decision |
| Note Levels three and five have minimum dollar amounts that CMS updates each year. Medicare Advantage plans, Medicaid plans, and commercial payers use their own appeal rules, and their deadlines are often shorter than Medicare’s. The deadline is printed on the denial letter or remittance, so put it on your calendar the day the denial arrives. |
Appeals are worth the effort. In KFF’s analysis of 2024 Medicare Advantage data, only 11.5% of denied prior authorization requests were appealed, yet 80.7% of those appeals were fully or partially overturned. Not every service needs the same kind of approval, so it helps to know the different authorization types in medical billing before you build your payer checklist.
Which Numbers Should You Track?
You cannot fix what you do not measure. These six numbers give a clear picture of how your practice is doing.
| Measure | What it tells you | How to calculate it |
| Initial denial rate | How often claims are refused on first submission | Denied claims divided by claims submitted |
| First-pass acceptance rate | How clean your claims are when they leave | Claims paid or accepted on first try divided by claims submitted |
| Denials by reason and payer | Where the problems are concentrated | Group denials by code, payer, and provider |
| Appeal win rate | Whether your appeals are well built | Appeals paid divided by appeals filed |
| Days in accounts receivable | How fast you get paid | Total receivables divided by average daily charges |
| Denial write-offs | Money lost for good | Dollars written off because of denials, tracked monthly |
Review these monthly. If one payer or one denial code keeps showing up, that is where to spend your time first.
When to Get Help With Denial Management
Many practices handle denials in-house until the workload outgrows the team. Signs that it is time for more support include a denial rate that keeps rising, appeals that sit past their deadlines, staff who spend more time on rework than on patients, and cash flow that is slower than your visit volume would suggest.
An experienced medical billing partner can review your denial reports, spot the patterns behind them, keep up with payer and code changes, and follow up on denied claims on a regular schedule. If you are weighing this option, ask any partner how they report denial data, how they handle appeals, and how they will train your front desk to prevent repeat problems.
Frequently Asked Questions
What is the most common reason medical claims are denied?
Eligibility and registration problems are most often listed first, including wrong patient details, expired coverage, and the wrong payer. Missing prior authorization, medical necessity issues, and coding errors follow closely. Most of the top causes start before or at the visit.
What is a good claim denial rate?
The American Academy of Family Physicians calls 5% to 10% typical and a rate under 5% desirable. Rates vary by specialty and payer mix, so compare your practice to its own past results first.
Can I resubmit a denied claim?
Yes, if the denial is for something you can correct, such as a missing modifier or wrong information. Use the payer’s corrected claim process. If you disagree with the payer’s decision, file an appeal instead of resubmitting the same claim.
How long do I have to appeal a denied claim?
It depends on the payer. Original Medicare gives you 120 days from receipt of the initial determination for the first appeal. Other payers set their own limits, which are often shorter, and the denial notice states the deadline.
Is it worth appealing small-dollar denials?
Often yes, especially when the same error repeats. One corrected process can prevent dozens of future denials. For low-value claims, weigh the staff time against the payment, and focus on fixing the cause instead of appealing every case one by one.
Will the new prior authorization rule reduce denials?
It should speed up decisions and make denial reasons clearer for the government-regulated plans it covers. It does not remove prior authorization, it does not cover most employer-sponsored commercial plans, and the electronic systems it requires mostly arrive in 2027. Your practice still needs a solid authorization process.
Are Medicare telehealth claims still payable in 2026?
Yes. Congress extended Medicare telehealth flexibilities through December 31, 2027. Make sure each claim has the right place of service and modifier, and check any telehealth denials from the periods when the flexibilities briefly lapsed.
Final Thoughts
Claims are denied in 2026 for reasons that are mostly familiar: coverage that was not verified, authorizations that were missing or did not match, notes that did not show medical necessity, and codes that did not follow the latest rules. What has changed is that payers check more of these items automatically, so small mistakes cost more than they used to.
The practices that keep denials low treat them as a team problem and not only a billing problem. They verify early, document clearly, scrub every claim, read denial codes carefully, appeal on time, and review the numbers every month.
| Need help lowering your denial rate?If denials are slowing your cash flow and your team is stretched thin, Proactive Healthcare Services (PHCS) can review your denial reports, find the patterns behind them, and support your medical billing so more claims are paid the first time. Contact PHCS to discuss your practice. |
