CPT Code 90834: The 45-Minute Psychotherapy Billing Guide

The backbone code of most outpatient therapy practices — how to document, bill, and avoid denials on the session length you’ll use most.

CPT code 90834 is used to bill for psychotherapy sessions of approximately 45 minutes. For most independent therapists in outpatient private practice, 90834 is the single most frequently billed code. It carries lower audit scrutiny than 90837, reimburses at a reasonable rate, and fits the typical structure of a standard therapy hour.

This guide covers the exact time window for 90834, documentation requirements, how it differs from 90837 and 90832, and the mistakes that most commonly generate denials.

The time window for 90834

The CPT description for 90834 is “Psychotherapy, 45 minutes with patient.” The reportable range for 90834 is 38 to 52 minutes of psychotherapy with the patient present.

A 50-minute therapy hour falls squarely inside the 90834 range. A session that runs long and clears 53 minutes shifts to 90837. A session cut short that runs 35 minutes drops to 90832.

Why 90834 is the safest default

90834 is the billing code most aligned with how outpatient therapy has been structured for decades. The traditional 50-minute hour fits cleanly inside the 38–52 minute window. Payers expect it. Auditors see it as consistent with clinical norms.

The OIG has identified high-frequency 90837 billing as an audit focus area. By contrast, 90834 has not been flagged as a utilization concern at the same level. This does not mean you should downcode from 90837 to 90834 to avoid audit risk — that creates its own compliance problem. It means that when your actual session length is 45 to 50 minutes, 90834 is both clinically accurate and strategically lower-risk.

Documentation requirements for 90834

The core documentation elements for 90834 are the same as any time-based psychotherapy code:

• Start and stop time of the psychotherapy component, or total face-to-face psychotherapy time
• Active diagnosis supporting medical necessity
• Specific therapeutic interventions used during the session
• Patient response to those interventions
• Connection to the treatment plan
• Plan for the next session

The time documentation piece is where most denials originate. A note that records only “45-minute session” is weaker than one that records “therapy 2:03p–2:50p, total 47 minutes.” The specific time detail allows an auditor to verify that the 38-minute floor was met.

How 90834 reimburses

Medicare reimbursement for 90834 is set annually in the Medicare Physician Fee Schedule and is adjusted by locality. Reimbursement is lower than 90837 but higher than 90832. As of the most recent rulemaking, LCSWs, LPCs, and LMFTs all receive the same reimbursement rate for 90834, billed to their own Medicare provider number.

Commercial payer rates vary significantly. Some payers use Medicare as a benchmark and pay a percentage; others have their own fee schedules. Your contracted rate with each payer is what determines the actual reimbursement.

Common denial reasons for 90834

Time not documented

The single most common denial is inadequate time documentation. Session notes must make the time billable verifiable.

Diagnosis does not support psychotherapy

Medicare requires a covered mental health diagnosis that supports psychotherapy as medically necessary. Claims submitted with diagnoses that do not support psychotherapy — or with only V-codes or Z-codes — are frequently denied.

Missing treatment plan

Medicare expects an active treatment plan that is current and supports ongoing psychotherapy. Notes that are not connected to a documented treatment plan, or that reference a plan that is more than 90 days old without documented updates, can be flagged on audit.

Incident-to billing issues

If you are working under incident-to billing rules with a supervising physician, the documentation requirements include additional elements beyond the standard psychotherapy note. Incident-to errors are a recurring source of denials.

90834 vs. 90837 — picking the right code

The right code is always the one that matches the actual length of psychotherapy provided. If your session ran 47 minutes, you bill 90834. If it ran 55 minutes, you bill 90837. Code selection follows clinical reality, not reimbursement preference.

For therapists whose standard appointment block is 50 minutes or less, 90834 will naturally be the most frequently used code. For those whose blocks are 60 minutes and sessions consistently run 53 minutes or longer, 90837 is appropriate. What matters is that your code selection, documentation, and actual session length all align.