The three time-based psychotherapy codes — 90837, 90834, and 90832 — account for the large majority of claims submitted by independent therapists billing Medicare. Getting the documentation right for these codes is the single most important compliance task for a solo private practice.
Here's a plain-English breakdown of what Medicare requires for each code, and where therapists most commonly create documentation gaps.
Time range: 53 minutes or more of psychotherapy. This is the most commonly billed code in private practice — and the most closely audited by Medicare contractors.
90837 requires documentation of a full hour (technically 53+ minutes) of psychotherapy time. The session note must include the start and stop time of the psychotherapy component, a statement of medical necessity connecting the patient's current clinical status to the ongoing need for treatment, and documentation of the patient's response to interventions provided in the session.
Because 90837 is the highest-reimbursed psychotherapy code, it is also the one most likely to be downgraded during a medical necessity review. If your notes don't affirmatively support the need for ongoing 60-minute sessions versus shorter interventions, an auditor may recode your claims to 90834 or 90832 and demand repayment of the difference.
Time range: 38–52 minutes of psychotherapy. Requires documented start/stop times and medical necessity narrative.
The 90834 billing error that appears most often in Medicare audits is the absence of start/stop time documentation. A note that says the session was 45 minutes long — without documenting when the therapy component began and ended — is technically deficient. Some EHR systems auto-populate session duration from appointment scheduling; this is not sufficient if the scheduled time doesn't match the actual therapy time provided.
Time range: 16–37 minutes of psychotherapy. Lower reimbursement, but subject to pattern analysis by Medicare contractors.
90832 is often used for brief therapeutic check-ins or in conjunction with evaluation and management services. Medicare contractors analyze the ratio of 90832 to 90834/90837 billing for individual providers — an unusually high proportion of 30-minute sessions relative to peer therapists in your area can trigger a billing pattern review, even if every individual claim is documented correctly.
Regardless of which psychotherapy code you're billing, Medicare expects your session note to document: the diagnosis and how it relates to the services provided; the patient's current functional status and clinical presentation; the specific interventions used; the patient's response to those interventions; and progress (or documented lack of progress with clinical rationale) toward treatment plan goals. And for all three codes: the start and stop time of the psychotherapy service.
Documentation requirements evolve: CMS periodically updates guidance on what constitutes adequate medical necessity documentation for mental health services. TherapyBillingClarity.com monitors these changes and delivers plain-English summaries to your inbox monthly. Learn more →