Practice type: Solo outpatient psychology practice Provider: 1 licensed psychologist (PhD) Location: United States Patient volume: Approximately 120 patient encounters per month Payer mix: 41% commercial (BCBS, Aetna, UHC), 28% Medicare, 22% Medicare Advantage, 9% self-pay Services: Individual psychotherapy, psychological testing and evaluation, psychiatric diagnostic evaluations, group therapy, telehealth sessions
Background
Solo behavioral health practices have a billing problem that’s different from group practices not in kind, but in scale. There’s one provider. One set of credentials. And typically one person handling everything from scheduling to billing to insurance follow-up alongside full-time clinical work.
This psychologist had been in solo practice for eight years. She was clinically excellent, fully booked, and financially stable but not financially optimized. Billing had always been something she managed herself with help from a part-time front office assistant who came in twice a week. Claims went out through her EHR’s built-in billing module. Money came in. She paid her assistant and moved on.
She contacted Malakos Healthcare Solutions after a conversation with a colleague who had recently completed a billing audit and discovered she had been underbilling for years. The psychologist’s question was simple: “Is that happening to me too?”
The answer, as we discovered during the audit, was yes and in several ways she hadn’t considered.
The Initial Audit – What We Found
Malakos conducted a full revenue cycle audit covering twelve months of claims data, a review of forty session notes across all service types, six months of ERA and EOB records, and a complete AR aging analysis.
The practice was generating approximately $18,400 per month in collections. The audit identified that it should have been generating closer to $31,000 per month a gap of $12,600 per month, or $151,200 per year, driven by seven specific billing problems.
Finding 1 – Psychotherapy Time Codes Applied to Scheduled Duration, Not Documented Time
This was the most pervasive billing error in the practice and the one with the most compliance exposure.
Behavioral health psychotherapy is billed using time-specific codes:
- CPT 90832 — 30-minute therapy (16–37 minutes)
- CPT 90834 — 45-minute therapy (38–52 minutes)
- CPT 90837 — 60-minute therapy (53+ minutes)
The code billed must match the documented therapy time not the scheduled session duration.
This practice scheduled all sessions in 50-minute blocks. Every session had been billed at 90834 (45-minute code) without anyone ever reviewing the actual documented session time.
A review of forty session notes showed significant variation in actual documented time:
- 14 sessions documented 53+ minutes of psychotherapy supporting 90837 (60-minute code)
- 19 sessions documented 38–52 minutes correctly supporting 90834
- 7 sessions documented fewer than 38 minutes due to patient late arrivals, early terminations, or brief check-in sessions
The 14 sessions that supported 90837 were being billed at 90834 undercoding by one time tier. The 7 sessions under 38 minutes were being billed at 90834 overcoding that created compliance exposure.
The psychologist had never been told that the billing code must reflect documented time, not scheduled time. She had assumed “50-minute sessions bill as 90834” was a fixed rule. It isn’t the rule is that documented time determines the code.
Annual revenue impact from psychotherapy time code undercoding: approximately $18,200 (based on 14 sessions per month at the rate differential between 90834 and 90837 under commercial and Medicare rates).
Annual compliance exposure from overcoded sessions: 7 sessions per month billed at 90834 when documentation supported only 90832. This was the more urgent finding not for the revenue impact, but for the audit risk on sessions where the claim said 38–52 minutes and the note documented fewer than 38.
Finding 2 – Psychological Testing Billed Under Single Code for All Components
The psychologist conducted approximately 4–6 psychological evaluations per month. These were comprehensive batteries involving initial clinical interview, standardized testing administration, scoring, interpretation, and written report preparation often taking 8–12 hours of total professional time across multiple sessions.
The correct billing framework for psychological testing separates three distinct components:
Test administration and scoring:
- CPT 96136 — Psychological test administration and scoring, first 30 minutes
- CPT 96137 — Each additional 30 minutes
Evaluation and interpretation:
- CPT 96130 — Psychological testing evaluation first hour (includes interpretation and report)
- CPT 96131 — Each additional hour
Every psychological evaluation had been billed under a single code 96130 regardless of total time invested in administration, scoring, and interpretation.
For an 8-hour evaluation battery, correct billing would include 96130 (first hour of evaluation) plus multiple units of 96131 (each additional hour of evaluation) plus 96136/96137 (test administration and scoring time). The practice was billing one unit of 96130 and nothing else collecting approximately $185 per evaluation when the documented professional time supported $620–$780 in correctly billed services.
Annual revenue gap from psychological testing underbilling: approximately $31,400.
This was the largest single revenue gap in the audit and the most surprising to the psychologist. “I just billed 96130 for every eval,” she said. “I had no idea there were separate codes for the testing hours.”
Finding 3 – Telehealth Claims Submitted With Wrong Place of Service Code
The practice had transitioned to approximately 60% telehealth following the pandemic and maintained that ratio. Every telehealth claim was being submitted with POS 11 (office) the same place of service code used for in-person sessions.
The correct POS code for telehealth visits where the patient is in their home is POS 10. Most commercial payers also require Modifier 95 (synchronous audio/video telehealth) on telehealth claims.
Of the 72 telehealth claims per month the practice was submitting:
- 0 had Modifier 95 applied
- 0 had POS 10 applied to patient-home telehealth visits
This was both a billing compliance error and a potential audit trigger. Medicare and most commercial payers have been auditing telehealth POS code accuracy since 2022. Claims showing POS 11 for sessions where the provider’s notes document the patient joining from home create a documentation-to-claim mismatch that is one of the most common behavioral health telehealth audit findings.
Annual revenue impact was indirect the wrong POS code wasn’t causing denials, but it was creating compliance exposure on 864 telehealth claims per year that could trigger retroactive recoupment if audited.
Finding 4 – Diagnostic Evaluation Code Selection Incorrect
When a new patient presented for an initial evaluation, the psychologist was billing CPT 90791 (psychiatric diagnostic evaluation without medical services) the correct code for a diagnostic evaluation by a non-prescribing behavioral health provider.
However, for patients referred for psychological testing who required a comprehensive diagnostic interview before testing began, the initial clinical interview was being bundled into the 90791 charge and not separately documented as the clinical interview component of the psychological evaluation.
The more significant error: for established patients presenting with new or significantly changed clinical presentations requiring a new diagnostic formulation not a routine therapy session 90791 was not being billed at all. These encounters were billed as standard therapy sessions (90834) even when the clinical documentation clearly described a re-evaluation, new diagnosis formulation, and treatment plan revision.
Annual revenue gap from incorrect diagnostic evaluation billing: approximately $12,800.
Finding 5 – Group Therapy Billed Per Group, Not Per Patient
The psychologist ran two weekly group therapy sessions of 6 patients each. CPT 90853 (group psychotherapy) is billed per patient per session one unit of 90853 for each patient who attends each group.
The practice had been billing one unit of 90853 per group session collecting for one patient’s group session when six patients attended. Every group session was billed at 1/6 of its correct reimbursement.
Annual revenue gap from incorrect group therapy billing: approximately $22,400.
This was the billing error that produced the strongest reaction in the audit meeting. “One unit for the whole group?” the psychologist said. “I’ve been running these groups for four years.”
Four years of two weekly groups, six patients each, billed as a single session each time.
Finding 6 – MHPAEA Parity Violation – Visit Limits Applied to Behavioral Health But Not Medical
During the payment reconciliation review, a pattern emerged with one of the commercial payers in the practice’s mix. The payer was applying a visit limit of 30 behavioral health sessions per year after which claims were denied for “benefit maximum reached.”
A review of the same payer’s medical benefit structure, accessed through their provider portal, showed no comparable visit limit on medical or surgical outpatient services for chronic conditions.
Under the Mental Health Parity and Addiction Equity Act (MHPAEA), this disparity a quantitative treatment limitation applied to behavioral health benefits that doesn’t apply to comparable medical benefits is a potential parity violation.
The practice had been accepting the post-30-visit denials as final and billing patients for sessions beyond the limit. No parity challenge had ever been filed. Several patients had discontinued treatment when they received bills for sessions they expected to be covered.
Annual revenue impact from unchallenged parity violations: approximately $14,200 in claims denied beyond the visit limit that should have been covered under parity.
Finding 7 – AR Aging With Unappealed Parity and Coverage Denials
The AR aging report showed $67,000 in outstanding balances. Of that:
- $14,000 in 0–30 days – normal pending adjudication
- $18,000 in 31–60 days – requiring follow-up
- $16,000 in 61–90 days – requiring escalation
- $11,000 in 91–120 days – at timely filing risk
- $8,000 in 120+ days – critically aged
The 61–120 day AR was almost entirely coverage denials and visit limit denials that had never been appealed including the parity violation denials described above. Without a structured denial management process, every denial was being accepted as final.
Audit Summary
| Revenue Gap | Annual Estimated Impact |
|---|---|
| Psychotherapy time code undercoding | $18,200 |
| Psychological testing underbilling | $31,400 |
| Group therapy billed per group vs. per patient | $22,400 |
| Diagnostic evaluation billing errors | $12,800 |
| Parity violation denials not challenged | $14,200 |
| AR denials not appealed | $24,000 |
| Telehealth compliance (indirect — no direct revenue impact, compliance risk) | — |
| Total identified revenue gap | $123,000 |
The audit meeting lasted nearly two hours. The psychological testing finding was the one that landed hardest.
“I spent an entire day on an evaluation. Eight hours. And I billed one code for $185,” she said. “I didn’t know. Nobody told me. My EHR defaulted to 96130 and I never questioned it.”
The group therapy finding produced something between frustration and disbelief. Four years of two groups per week, six patients each, billed as one patient per session.
The parity finding produced a different reaction concern. “Some of those patients stopped coming when they got the bill. If they had a right to continued coverage and I didn’t know to challenge it, that’s not just a billing problem. That’s a clinical problem.”
She signed with Malakos the following week.
The Transition – First 30 Days
Onboarding took nine business days. The practice used SimplePractice. Malakos continued working within SimplePractice no migration, no disruption to the clinical workflow.
Priority 1 — Telehealth compliance. Every telehealth claim from day one of onboarding included POS 10 for patient-home sessions and Modifier 95 for commercial payers. A retroactive review of the prior six months of telehealth claims was conducted to assess the scope of the POS error and advise on corrective action options.
Priority 2 — Psychotherapy time code correction. We worked with the psychologist to revise her session note format adding explicit documentation of therapy start and end time, creating a clear record of documented therapy minutes that could be verified at billing. The session note revision took one week to implement as a consistent habit.
Priority 3 — Psychological testing billing framework. We built a testing-specific charge capture reference showing the correct code combination for each phase of the evaluation process clinical interview (90791 where applicable), test administration and scoring (96136/96137), and evaluation and interpretation (96130/96131). The psychologist received a one-page testing billing guide showing how to track and document time across testing phases.
Priority 4 — Group therapy rebilling. We corrected the group billing workflow immediately 90853 submitted per patient per session from day one. For the prior six months of group sessions within the commercial payer timely filing window, we filed corrected claims billing the correct per-patient rate. Initial recovery from group billing corrections: $8,400 in the first 30 days.
Priority 5 — Parity challenge filing. We researched the specific commercial payer’s medical benefit structure, documented the MHPAEA quantitative treatment limitation disparity, and filed a formal parity complaint through the payer’s internal appeals process with supporting documentation. The complaint was accompanied by requests for the payer’s written comparative analysis of mental health and medical/surgical benefits, as required under MHPAEA regulations.
Priority 6 — AR backlog. Of the $27,000 in 61–120 day AR, $19,200 was still within commercial payer appeal windows. Appeals were filed in the first two weeks with clinical documentation supporting medical necessity and, where applicable, parity arguments for visit limit denials.
90-Day Results
Psychotherapy time code distribution:
| Code | Pre-Malakos | 90 days after |
|---|---|---|
| 90832 (30 min) | 0% | 6% |
| 90834 (45 min) | 100% | 59% |
| 90837 (60 min) | 0% | 35% |
The shift to 90837 for 60+ minute documented sessions added $1,400–$1,800 per month in revenue immediately. The 6% at 90832 reflected sessions where documented time genuinely supported only the lower code — appropriate downward correction that eliminated the compliance exposure.
Psychological testing billing: First month of correctly billed evaluations: 5 evaluations, average billing of $640 per evaluation vs. $185 previously. Month one testing revenue: $3,200 vs. $925 prior. Immediate revenue improvement of $2,275 per month from testing billing correction alone.
Group therapy billing: Corrected to per-patient billing from day one. Monthly group therapy revenue: $1,920 per month (2 groups × 4 weeks × 6 patients × $40 average) vs. $320 per month (same sessions billed as 1 unit each). Monthly improvement: $1,600.
Parity challenge outcome: The commercial payer responded to the formal parity complaint at day 72. After review, the payer acknowledged that the 30-visit behavioral health limit did not have a comparable medical benefit limitation and agreed to retroactively process denied claims beyond the 30-visit threshold going back 18 months. Total retroactive payment from parity resolution: $19,400.
The psychologist’s reaction to the parity resolution was direct: “That’s money those patients would have paid out of pocket if we hadn’t challenged it. Some of them did pay it. I’m figuring out how to handle refunds for those patients now.”
AR recovery from backlog appeals: $16,800 recovered from the 61–120 day denial backlog through formal appeals filed in the first two weeks. $2,400 was beyond recovery past appeal windows. $7,800 remained in active appeal at the 90-day mark.
Days in AR: Pre-Malakos: 56 days average 90 days after: 36 days average
12-Month Results
| Metric | Pre-Malakos | 12 months with Malakos |
|---|---|---|
| Total net collections | $220,800 | $376,800 |
| Psychotherapy at 90837 | 0% | 35% |
| Psychological testing revenue/eval | $185 avg | $640 avg |
| Group therapy revenue/session | $53 (1 unit) | $320 (6 units) |
| Telehealth POS compliance | 0% | 100% |
| Parity challenge filed and won | Never attempted | $19,400 recovered |
| Overall denial rate | 21.3% | 6.8% |
| Days in AR | 56 days | 34 days |
Total revenue improvement year-over-year: $156,000
The gap between the $123,000 identified in the audit and the $156,000 recovered reflects the parity resolution retroactive payments, the group billing correction backlog recovery, and the compounding effect of correctly billed psychological testing as the patient volume for evaluations grew through the year.
What the Practice Said
At the one-year review, the psychologist reflected on what the experience had changed:
“I went into this thinking billing was an administrative function I was managing adequately. I was wrong on both counts. It wasn’t administrative — it was clinical in the sense that the billing gaps were affecting my patients. And I wasn’t managing it adequately. I was doing what I learned when I set up the practice and never questioned it.”
On the psychological testing finding specifically:
“Eight years of billing one code for comprehensive evaluations. Eight years. I’m a psychologist — I know how to conduct a proper evaluation. I had no idea how to bill for one. Those are different skills and nobody taught me the second one.”
On the parity challenge:
“The fact that I can now tell patients their behavioral health coverage has the same terms as their medical coverage — and back that up with an actual parity complaint I filed and won — that changed something in how I practice. I stopped apologizing for what insurance does and doesn’t cover. I started questioning it.”
Key Takeaways
Psychotherapy time codes must reflect documented time, not scheduled duration. A 50-minute scheduled session that runs 55 minutes supports 90837. A 50-minute scheduled session where the patient arrived 15 minutes late supports 90832. The schedule is irrelevant. The documentation controls the code.
Psychological testing is systematically underbilled in solo psychology practices. The separation of test administration (96136/96137) from test evaluation and interpretation (96130/96131) is not intuitive — but it is required for correct billing of comprehensive evaluation batteries. Most solo psychologists billing a single 96130 for every evaluation are collecting 20–30% of what their documented professional time supports.
Group therapy billed per group instead of per patient is one of the most expensive billing errors in behavioral health. 90853 is a per-patient code. Billing it per group means collecting for one patient when six attended. This error runs silently for years in practices that were never taught otherwise.
MHPAEA parity is a legal right that most behavioral health providers never exercise. Commercial payers impose visit limits, prior authorization requirements, and reimbursement structures on behavioral health benefits that they don’t apply to comparable medical benefits — in direct violation of federal law. Most practices accept these limitations without challenge. A formal parity complaint, filed with documentation, has a meaningful resolution rate — and can recover substantial revenue on claims that were wrongly denied.
Is Your Behavioral Health Practice Missing Similar Revenue?
If your practice uses a single psychotherapy code for all sessions regardless of documented time, bills psychological evaluations under a single code, or accepts visit limit denials without a parity review — there is almost certainly a version of this case study sitting in your billing right now.
Malakos Healthcare Solutions offers a free behavioral health billing audit that identifies your specific revenue gaps in specific dollar terms.
No commitment. No obligation. Just a clear picture of what your practice is collecting — and what it should be.
Schedule Your Free Behavioral Health Billing Audit
📞 +1 (307) 441-3431 ✉️ support@malakoshcs.com 📍 Cheyenne, Wyoming — Serving behavioral health providers nationwide
This case study represents a composite of common billing challenges and outcomes seen across behavioral health practices. Practice details have been generalized to protect confidentiality.
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