Behavioral health has the highest first-pass denial rate of any outpatient specialty, and a large share of those denials are never appealed because the person who would appeal them is booked with clients all day. Almost all of it is preventable at the front end. The billing itself is not complicated once you know the handful of rules that actually generate the denials.
Who does the billing, and what most therapists use
In a solo or small group practice the biller is usually the clinician or a part-time office manager, working inside an EHR built for notes rather than claims: SimplePractice, TherapyNotes, TheraNest, or a network like Alma, Headway, or Grow Therapy that takes a cut to handle it for you. Those tools are good at scheduling and documentation. Where practices bleed is the next step: scrubbing the claim before it goes out, reading the remittance when it comes back wrong, and working the denial before the filing window closes.
The codes you will actually bill
Ninety percent of a therapy practice runs on a short list. The individual psychotherapy codes are chosen by the face-to-face time you document, so the clock matters.
| Code | What it is | The rule that trips people |
|---|---|---|
| 90791 | Diagnostic evaluation, no medical services | Usually once per episode of care; billable by non-prescribers including LMFT and LPC |
| 90792 | Diagnostic evaluation with medical services | Prescribers only (MD, DO, NP, PA) |
| 90832 | Individual psychotherapy, 30 min | 16 to 37 minutes of face-to-face time |
| 90834 | Individual psychotherapy, 45 min | 38 to 52 minutes; the workhorse code |
| 90837 | Individual psychotherapy, 60 min | 53 minutes or more; the most-audited code (see below) |
| 90846 | Family psychotherapy, patient not present | Document why the patient was absent |
| 90847 | Family or couples psychotherapy, patient present | The identified patient has to be in the room |
| 90853 | Group psychotherapy | Per patient, per session |
| 90785 | Interactive complexity add-on | Add-on only, never alone, only with a real communication barrier |
| 90839 / 90840 | Crisis psychotherapy, first 60 min / each add'l 30 | Time-based; documents the crisis and the time |
Prescribers also bill an evaluation and management code (99202 to 99215) with a psychotherapy add-on (90833, 90836, or 90838) when a med-management visit includes therapy. That pairing has its own documentation rules and is a separate denial source.
The 90837 problem
90837 pays more than 90834, so payers watch it. Optum, Cigna, and others send letters when a provider's 90837 usage looks like an outlier compared to peers, and some will ask for records or push you toward 90834. The defense is simple and boring: document the actual start and stop time, or the total face-to-face minutes, in every note. If the time supports the code, you bill the code. Downcoding to 90834 to avoid attention is as much a compliance problem as upcoding, and it gives away revenue you earned.
Telehealth, the part that changes every year
Teletherapy is now most of many practices, and the place-of-service code drives the payment.
- POS 10 means the patient was in their home. It pays at the higher non-facility rate, which is what most private-practice teletherapy should use.
- POS 02 means the patient was somewhere other than their home. It pays at the lower facility rate.
- Modifier 95 is appended for synchronous audio-video sessions. Modifier 93 covers audio-only where the payer allows it.
- GT is legacy. Most payers retired it in favor of 95. Using GT out of habit causes rejections at some payers.
The federal telehealth flexibilities run on short-term extensions, so the safe habit is to confirm the current place-of-service and modifier requirements at the start of each year rather than trusting last year's setup.
The Medicare change worth knowing
As of January 1, 2024, licensed marriage and family therapists and mental health counselors (the Medicare label for many LPCs and LPCCs) can enroll in Medicare and bill directly, at 75 percent of the physician fee schedule amount. LCSWs were already eligible. The catch is enrollment: you have to complete PECOS enrollment before you can bill a single Medicare claim, it takes weeks, and there is no retroactive billing for work done before your effective date. A new solo practice that starts seeing Medicare patients before enrollment clears is working for free during the gap.
The denials that hit behavioral health hardest
| Code | What it usually means here | The fix |
|---|---|---|
| CO-96 / CO-109 | Provider not credentialed with the plan, or wrong taxonomy | Finish enrollment; confirm the taxonomy on the claim matches the license |
| CO-197 | Authorization required and absent (common for EAP and some plans) | Verify auth requirements at intake; EAP sessions almost always need one |
| CO-18 | Duplicate, often two sessions on the same day | Add the correct add-on or a distinct session note; confirm it is not a true duplicate |
| CO-29 | Timely filing | Track the window per payer; see the filing cheat sheet |
| Medical necessity (90837) | Records requested to justify the 60-minute code | Send the timed note; this is why you document start and stop time |
Every one of these is decodable the moment the remittance lands. Paste the reason code into the denial code decoder and it tells you who owes the balance and what the next step is.
Common questions, answered
What is the difference between 90834 and 90837?
Session length. 90832 is 16 to 37 minutes, 90834 is 38 to 52, and 90837 is 53 minutes or more. Document the time in the note. 90837 pays more and is audited more, so the timed note is your protection.
Can I bill 90837 and 90785 together?
Yes, when it is warranted. 90785 is an add-on reported with the psychotherapy code, never on its own, and only when a real communication barrier is present: a young child, a disruptive third party, a court-involved caregiver, or an interpreter. Routine use of 90785 is a known audit flag.
Does 90847 require the patient to be present?
Yes. 90847 is family or couples therapy with the identified patient in the room. 90846 is the version without the patient present. Bill the one that matches who actually attended, and note it.
Can an LPC or LMFT bill Medicare in 2026?
Yes, since January 1, 2024. LMFTs and mental health counselors can enroll and bill Medicare directly at 75 percent of the physician fee schedule. You must complete PECOS enrollment first, and there is no billing for dates of service before your effective date.
For teletherapy, do I use POS 10 or POS 02?
POS 10 for a patient in their home (higher, non-facility rate), POS 02 for a patient anywhere else (facility rate). Add modifier 95 for audio-video, 93 for audio-only where allowed. Skip GT; it is retired at most payers.
How often can you bill 90791?
Generally once at the start of an episode of care. A repeat evaluation after a long gap or a major change may be allowed but can need authorization. 90792 is the prescriber version with a medical component.