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Why Therapy Insurance Claims Get Denied (and How to Fix Them)

For owners and office managers of therapy, counseling and behavioral health practices

If you run a practice that takes insurance, denied claims are part of life. A denial is more than an annoyance, though. Every one delays payment, takes staff time to investigate, and risks becoming money you never collect if nobody follows up before the payer's deadline. The good news is that most denials come from a fairly short list of causes, and most of those can be prevented with better processes at the front end.

This guide covers the most common reasons mental health claims get denied and what you can do about each.

1. Eligibility and coverage problems

The most common cause is also the most preventable: the client's coverage wasn't active, the plan changed, or the policy details on file were wrong. Clients change jobs, switch plans at open enrollment, or move between Medicaid managed care plans. Often the practice only finds out when the denial arrives.

These usually appear with adjustment reason codes such as CARC 27 (expenses incurred after coverage terminated) or messages saying the patient can't be identified as an insured.

How to fix it: Verify eligibility and benefits before the first session, and re-verify regularly, ideally before each session for clients whose coverage is likely to change. Confirm that outpatient behavioral health benefits are active, not just medical coverage. Some plans carve behavioral health out to a separate administrator, so the claim has to go to a different payer than the one on the client's card.

2. Missing or invalid prior authorization

Some plans require authorization for certain services, a visit count above a threshold, or specific levels of care such as intensive outpatient. If a session falls outside an active authorization, or the authorization has run out of visits, the claim will be denied (often CARC 197, precertification/authorization absent).

How to fix it: Track authorizations by client, including start date, end date and number of approved visits, and set reminders before they expire. Note which payers and plans need authorization for which services, because the rules vary.

3. Credentialing and enrollment issues

If the rendering clinician isn't credentialed with the payer, or their enrollment hasn't been finalized or linked to the group's tax ID and NPI, claims may deny or pay out-of-network. This is especially common when a group hires a new clinician and they start seeing clients before payer enrollment is complete.

How to fix it: Keep a credentialing tracker for every clinician and payer combination. Before scheduling insured clients with a new clinician, confirm that the effective date is in place and that the claim will list the correct rendering and billing NPIs.

4. Coding errors and mismatches

Behavioral health has its own set of CPT codes: diagnostic evaluations (90791, 90792), psychotherapy by time (90832, 90834, 90837), family psychotherapy (90846, 90847), group psychotherapy (90853), and add-on codes such as interactive complexity (90785). Denials happen when:

• the code doesn't match the documented session time
• an add-on code is billed without a valid primary code
• the diagnosis code is missing or not specific enough, or doesn't support the service
• the payer doesn't cover a particular code for that provider type

How to fix it: Make sure documentation records start and stop times where the code depends on time, and that the note supports the code billed. Review your most common codes against each major payer's policies at least once a year.

5. Telehealth billing errors

Since telehealth became routine in therapy, a new category of denials has appeared: the wrong place of service code, a missing modifier, or billing an audio-only session as if it were video. Payers don't all follow the same telehealth rules.

How to fix it: Keep a simple payer grid showing which place of service code (for example 02 or 10) and which modifier (such as 95, or 93 for audio-only where accepted) each payer expects. Update it whenever payers publish policy changes. Our separate guide on telehealth therapy billing covers this in more detail.

6. Timely filing limits

Every payer sets a deadline for submitting claims, and a separate deadline for corrected claims and appeals. Miss it and the claim is usually denied for timely filing (CARC 29), and it often can't be recovered. These limits vary by payer and contract, so there's no single number to rely on.

How to fix it: Submit claims promptly after each session, ideally within days. Run an aging report regularly and work anything that has had no response before it gets close to the deadline. Keep proof of the original submission date (clearinghouse acceptance reports), because it can support an appeal.

7. Missing information and front-end rejections

Not every problem is a denial. Rejections happen before the claim is even accepted into the payer's system, because of missing or invalid data: a wrong subscriber ID, a date of birth that doesn't match, a missing NPI or taxonomy code, or an address formatting issue. Rejected claims are dangerous because they can look "submitted" in your system while the payer has no record of them.

How to fix it: Check clearinghouse rejection reports every day, fix and resubmit quickly, and don't assume a claim is in process until the payer has acknowledged it.

8. Coordination of benefits and duplicates

If a client has more than one plan, payers may deny the claim until coordination of benefits information is updated, often by the client. Duplicate claim denials (such as CARC 18) happen when a claim is resent instead of being submitted as a correction or a status check.

How to fix it: Ask about secondary coverage at intake and every year. When a claim needs changing, submit it as a corrected claim using the appropriate frequency code rather than as a new original claim.

Turning denials into a process

The practices that collect the most aren't the ones that never get denials. They're the ones that work denials consistently. A simple process looks like this:

1. Review remittances and denials every week.
2. Group denials by reason, so you can fix the root cause, not just the claim.
3. Correct and resubmit, or appeal, well inside the payer's deadlines.
4. Follow up on any claim with no response after a reasonable period.
5. Report monthly on what is open, what was recovered, and what was written off and why.

If your team doesn't have time for this, unpaid claims quietly pile up in A/R.

Need help with denied or unpaid claims?

MedBill Solutions works with US therapy and behavioral health practices on claims, denial follow-up and payer follow-up. If you have old unpaid claims sitting in A/R, we'll work them and you only pay 3% of what we recover. Ongoing billing starts at 3% of what we collect for you.

Get your old claims reviewed → or email medbillsolutionsusa@gmail.com. Please don't send patient information until a Business Associate Agreement is in place.

This article is general information, not legal or coding advice. Payer rules change, so always check the current policies of the payers you bill.

More resources

• How to Bill Telehealth Therapy Sessions: Codes, POS and Modifiers
• Should a Small Group Practice Outsource Billing?