Group Therapy Billing in Physical Therapy: Medicare Rules, CPT 97150, and Documentation Guide 2025

Group therapy can be a powerful tool for increasing practice efficiency while delivering quality patient care—but Medicare billing rules for CPT 97150 are specific, complex, and frequently misunderstood. Get it wrong, and your practice faces claim denials, audit scrutiny, or worse: allegations of improper billing that could result in substantial penalties.

As Medicare audits intensify in 2025, understanding the precise distinctions between group therapy, concurrent therapy, and individual treatment has never been more critical. This comprehensive guide walks you through the official CMS guidance, billing scenarios, documentation requirements, and common pitfalls that trigger Medicare audits.

What Is Group Therapy Under Medicare Part B?

Group therapy (CPT 97150) is defined by Medicare as therapeutic procedures provided simultaneously to two or more individuals by a licensed practitioner. According to CMS billing guidelines, the patients can be—but do not need to be—performing the same or similar activities under Medicare Part B.

Key Requirements for CPT 97150

Minimum of two patients engaged in therapeutic activities at the same time
Therapist must be in constant attendance throughout the session
One-on-one patient contact is NOT required—the therapist oversees the group but doesn’t need to provide hands-on intervention to each patient continuously
Patients do not need the same diagnosis or be working toward the same goals
No maximum group size under Medicare Part B (though clinical judgment and quality care standards should guide group composition)

What Group Therapy Is NOT

Group therapy is not supervision of patients exercising independently on equipment. Medicare explicitly states that “supervision of a previously taught exercise program or supervising patients who are exercising independently is not a skilled service and is not covered as group therapy.” The therapist must be actively delivering skilled intervention, providing cues, feedback, and therapeutic modifications throughout the session.

Understanding PT CPT codes for 2025 helps contextualize where group therapy fits within your overall coding strategy, as it’s fundamentally different from time-based individual therapy codes.

The Critical Distinction: Group vs. Concurrent Therapy

This is where many practices make costly billing mistakes. While the terms “group therapy” and “concurrent therapy” are sometimes used interchangeably in clinical settings, they are NOT the same under Medicare billing rules—and the difference has significant reimbursement implications.

Group Therapy (CPT 97150) - Part B Definition

Under Medicare Part B, group therapy is billed when two or more patients receive treatment at the same time, regardless of whether they’re performing the same or different activities. The key characteristic is that multiple patients are being treated simultaneously.

As confirmed by Medicare billing guidelines, “For Medicare Part B, the treatment of two patients (or more), regardless of payer source, at the same time, regardless of activity, is documented as group treatment.”

Concurrent Therapy - Part A Only

Concurrent therapy is a form of group therapy, but is NOT recognized by Medicare Part B. This is a critical compliance point that many practices overlook.

Concurrent therapy is defined as simultaneous treatment of two patients who are performing different activities. This billing mode exists only under Medicare Part A (skilled nursing facilities) as part of the Patient Driven Payment Model (PDPM).

According to ASHA’s guidance on group and concurrent therapy, “Concurrent therapy is not a billable service under Medicare Part B. Medicare Part A policies can vary.”

Why This Matters for Your Practice

If you’re treating outpatient Medicare Part B patients:

DO NOT attempt to bill concurrent therapy codes—they will be rejected
Any scenario involving two or more patients treated simultaneously = bill as group therapy (97150)
The activities patients perform (same or different) are irrelevant for Part B billing
Part B patients may not be treated concurrently in the Part A sense—all multi-patient treatment defaults to group therapy billing

This distinction becomes even more important when you consider audit-proof documentation requirements, as misclassifying concurrent therapy can trigger red flags during Medicare reviews.

Medicare Billing Rules for CPT 97150 in 2025

Understanding the specific billing mechanics of CPT 97150 is essential for accurate claims submission and revenue optimization.

CPT 97150 Is an Untimed Code

Unlike most physical therapy procedure codes that follow the Medicare 8-minute rule, CPT 97150 is billed as one unit per patient per session regardless of duration. This is fundamentally different from time-based codes like 97110 (therapeutic exercise) or 97140 (manual therapy).

Billing Logic:

Group session lasting 30 minutes with 3 patients = bill 97150 x 1 unit for each patient (3 separate claims)
Group session lasting 60 minutes with 4 patients = bill 97150 x 1 unit for each patient (4 separate claims)
The time spent does NOT affect the number of units billed per patient

Constant Attendance Requirement

The therapist providing group therapy must be in constant attendance throughout the session. This means:

The therapist remains present and engaged with the group at all times
The therapist cannot leave the group to attend to another patient
The therapist CANNOT provide one-on-one treatment to a different patient while simultaneously overseeing the group—this is a common audit trigger

If a therapist steps away to provide individual treatment to another patient, the group session must be paused, or billing must reflect only the time when the therapist was present with the group.

Billing Group and Individual Therapy on the Same Day

You can bill for both group therapy (97150) and individual one-on-one therapy codes on the same day for the same patient, but there are strict requirements:

According to the CMS 11 Part B Billing Scenarios, the National Correct Coding Initiative (NCCI) edits require that:

The group therapy and individual therapy must occur in different sessions, timeframes, or separate encounters that are distinct and independent
You must use Modifier 59 to indicate that the services represent separate sessions on the same day
Your documentation must clearly demonstrate that these were distinct therapeutic interventions, not overlapping activities

Example of Compliant Same-Day Billing:

9:00-9:30 AM: Individual therapeutic exercise (97110) for strengthening and manual therapy (97140) = bill time-based units
10:00-10:45 AM: Group therapy session with 3 patients for balance activities (97150) = bill 1 unit with Modifier 59

The modifier 59 signals to Medicare that these were separate, medically necessary sessions.

Required Modifiers for CPT 97150

Always include the appropriate therapy-type modifier when billing 97150:

GP modifier - Physical therapy services
GO modifier - Occupational therapy services
GN modifier - Speech-language pathology services

Additionally, if services are provided in whole or in part by a Physical Therapist Assistant (PTA) or Occupational Therapy Assistant (OTA), you must apply the appropriate CQ or CO modifiers. Learn more about PTA supervision requirements and modifier rules for 2025.

No Limit on Group Size Under Part B

While Medicare Part A has specific restrictions (including the 25% cap discussed below), Medicare Part B does not establish a maximum number of patients who can participate in a group therapy session.

However, clinical judgment, quality of care standards, state practice acts, and professional ethics must guide your decision. A therapist providing meaningful skilled intervention to 10 patients simultaneously would be difficult to justify clinically, even if technically permissible under Part B rules.

Understanding the 25% Cap for SNF/Part A Settings

If your practice provides therapy services in a skilled nursing facility (SNF) or you bill Medicare Part A, you must comply with the 25% limit on group and concurrent therapy implemented under the Patient Driven Payment Model (PDPM).

What Is the 25% Rule?

According to Noridian Medicare’s guidance on concurrent and group therapy limits, therapy must be delivered on an individual basis for at least 75% of the total treatment for a therapy episode, from the start of care through the end of care, for each discipline (PT, OT, and SLP).

This means: No more than 25% of total therapy minutes can be provided using group or concurrent modes, combined, per discipline, per patient in a covered Medicare Part A stay.

Example:

Patient receives 1,000 minutes of physical therapy during SNF Part A stay
Maximum group/concurrent therapy minutes = 250 minutes (25%)
Minimum individual therapy minutes = 750 minutes (75%)

Why CMS Implemented This Cap

Under PDPM, payment is driven by patient characteristics, not therapy minutes. CMS was concerned that removing the minutes-based payment model would incentivize facilities to shift toward group and concurrent therapy to reduce labor costs while maintaining the same reimbursement. The 25% cap ensures that patients continue to receive primarily individualized, patient-centered care.

As ASHA’s analysis of the PDPM model notes, “CMS notes that more than 99% of therapy is now provided on an individual basis and that individual therapy ‘should be considered the primary therapy mode and standard of care in therapy services provided to SNF residents.’”

Compliance Monitoring and Penalties

SNFs must report group and concurrent therapy minutes on the PPS Discharge Assessment (item O0425) for all SNF Part A beneficiaries. CMS tracks compliance across the entire Part A stay.

Good news for minor violations: CMS has clarified that SNFs exceeding the 25% limit receive “a non-fatal warning edit”—a reminder of non-compliance—but no direct financial penalty. However, consistent patterns of exceeding the cap could trigger audits or quality-of-care investigations.

This Rule Does NOT Apply to Part B Outpatient Practices

If you’re billing Medicare Part B for outpatient services, the 25% cap does not apply to you. However, you should still ensure that group therapy is clinically appropriate and documented as medically necessary—not just a cost-saving measure.

CMS 11 Part B Billing Scenarios: Real-World Examples

CMS published the “11 Part B Billing Scenarios for PTs and OTs” document to clarify common billing questions. Let’s walk through key scenarios relevant to group therapy billing.

Scenario 1: Group Therapy with Patients Performing Different Activities

Clinical Situation: A physical therapist treats 3 Medicare Part B patients simultaneously for 45 minutes. Patient A works on standing balance activities at parallel bars. Patient B performs seated trunk strengthening exercises on a mat. Patient C practices sit-to-stand transfers. The therapist moves between patients, providing verbal cues, manual facilitation as needed, and real-time modifications.

Billing:

Bill CPT 97150 x 1 unit for Patient A (with GP modifier)
Bill CPT 97150 x 1 unit for Patient B (with GP modifier)
Bill CPT 97150 x 1 unit for Patient C (with GP modifier)

Key Point: Even though the patients are performing different activities, this is still group therapy under Part B. The therapist is in constant attendance providing skilled intervention to all three patients.

Scenario 2: Cannot Bill Group While Providing One-on-One to Another Patient

Clinical Situation: A PT has 3 patients in the gym. Two patients are performing therapeutic exercises under the therapist’s supervision while the therapist simultaneously provides hands-on manual therapy to a third patient.

Billing - INCORRECT:

❌ Do NOT bill 97150 (group therapy) for the two patients exercising
❌ Do NOT bill 97140 (manual therapy) for the patient receiving hands-on treatment

Billing - CORRECT: The therapist must choose:

Option A: If providing true one-on-one manual therapy, bill only for that patient using time-based codes (97140). The other two patients cannot be billed as group therapy because the therapist is not in constant attendance with them—they’re receiving one-on-one attention to a different patient.

Option B: If the therapist is actively engaged with all three patients (providing brief hands-on intervention while also cueing and supervising the other two), then bill all three as group therapy (97150 x 3).

Key Point: You cannot “double dip” by billing individual codes for one patient while also billing group codes for others during the same timeframe. This is a major audit red flag.

Scenario 3: Billing Both Group and Individual Therapy on the Same Day

Clinical Situation: A patient receives individual one-on-one gait training (97116) for 30 minutes in the morning, followed by a group therapy session (97150) in the afternoon for 40 minutes with three other patients working on balance activities.

Billing:

Morning session: Bill 97116 x 2 units (30 minutes = 2 units per 8-minute rule)
Afternoon session: Bill 97150 x 1 unit with Modifier 59

Documentation Requirements: Your daily note must clearly indicate:

Separate timeframes for each session (e.g., “9:00-9:30 AM individual gait training; 2:00-2:40 PM group balance activities”)
Different therapeutic interventions and goals addressed in each session
Medical necessity for both sessions

Key Point: Modifier 59 is essential to pass NCCI edits. Without it, Medicare will only pay for the lower-priced group therapy code.

Scenario 4: PT and OT Treating the Same Patient Simultaneously

Clinical Situation: A PT and OT both provide services to the same patient at the same time for 30 minutes, working together on transfer training.

Billing Options: According to CMS guidance, only one therapist can bill for the entire service, OR the therapists can divide the service units.

Option A: PT bills 97530 (therapeutic activities) x 2 units; OT bills nothing Option B: OT bills 97530 (therapeutic activities) x 2 units; PT bills nothing Option C: PT bills 97530 x 1 unit; OT bills 97530 x 1 unit (each claims half)

Key Point: Both therapists cannot bill for the full 30 minutes. This prevents duplicate billing for the same treatment time.

Group Therapy Documentation Requirements for 2025

Proper documentation is your best defense against claim denials and Medicare audits. Audit-proof documentation requires specific elements when billing CPT 97150.

What Must Be Documented for Group Therapy

According to Medicare documentation standards for therapy practices, your group therapy documentation must include:

1. Total Time in Group Session

Even though CPT 97150 is an untimed code, you must document the total time spent in the group session. This helps establish medical necessity and allows auditors to verify that skilled intervention occurred for a substantial duration.

Example: “Patient participated in 45-minute group therapy session for balance and fall prevention activities.”

2. Individualized Goals for Each Patient

Group therapy is still patient-centered. Your documentation must demonstrate that each patient’s participation addressed their specific, individualized goals—not just generic group objectives.

Poor Documentation: “Patients participated in group balance activities.”

Audit-Proof Documentation: “Patient participated in group balance activities to address Goal #2: Improve dynamic standing balance to reduce fall risk during ADLs. Patient demonstrated improved ability to maintain balance during weight shifts with verbal cueing, progressing from moderate assistance to minimal assistance over 45-minute session.”

3. Skilled Intervention Provided

Document the skilled therapeutic techniques, cues, manual facilitation, and clinical decision-making you provided to each patient. Remember: supervision of independent exercise is NOT billable.

Include:

Verbal cues and feedback provided
Manual facilitation or hands-on guidance
Real-time modifications based on patient response
Education provided about safety, proper technique, or home carryover
Clinical reasoning for activity selection and progression

Example: “During group standing balance activities, provided tactile cues to posterior hip musculature to improve weight-shifting symmetry. Modified activity mid-session by adding cognitive dual-task (counting backward) when patient demonstrated excessive focus on task without attention to environment—preparing for real-world functional balance demands.”

4. Each Patient’s Participation and Response

Document how each individual patient participated and responded to the intervention. This proves that group therapy was clinically appropriate for each person.

Include:

Level of assistance required
Patient’s engagement and effort
Progress toward individualized goals
Any modifications needed for that specific patient
Patient’s response to skilled intervention

5. Medical Necessity Justification

Link the group therapy session to the patient’s diagnosis, functional limitations, and plan of care. Explain why group therapy was medically appropriate for this patient at this time—not just a convenience for scheduling.

Audit-Proof Justification: “Group therapy format medically appropriate to simulate social/distracting environment encountered during community ambulation and to provide peer modeling for proper weight-shifting technique. Patient’s goal is to safely navigate crowded grocery store; group setting provides realistic challenge with controlled safety.”

6. Constant Attendance Verification

Your documentation should implicitly demonstrate that you were in constant attendance. Avoid language that suggests you left the group or were simultaneously treating other patients one-on-one.

Avoid: “Checked on patients periodically during exercise session.” Better: “Provided constant supervision with real-time cueing and progression throughout 40-minute group therapy session.”

Documentation Tips for Compliance

Use structured templates in your EMR that prompt for required elements (individualized goals, skilled intervention, patient response)
Link to Plan of Care: Reference specific goals from the certified POC—learn more about Medicare POC certification requirements for 2025
Be specific: Generic language triggers audits. Use concrete descriptions of patient performance and your clinical decision-making
Track progress over time: Show how group therapy is moving patients toward functional goals, not just maintaining current status
Document INABILITY to perform independently: If patients could perform these activities safely without skilled supervision, group therapy wouldn’t be medically necessary

Common Group Therapy Billing Mistakes to Avoid

Medicare scrutiny of therapy billing has intensified significantly in 2025. According to billing compliance research, the average penalty for non-compliant billing is $52,847 per clinic. Avoid these common pitfalls:

Mistake 1: Billing Concurrent Therapy for Part B Patients

The Error: Attempting to bill concurrent therapy codes or thinking of group therapy as “concurrent” for Medicare Part B patients.

Why It’s Wrong: Concurrent therapy is not recognized under Medicare Part B. Any situation with two or more patients treated simultaneously must be billed as group therapy (97150), regardless of whether activities are the same or different.

The Fix: Always use CPT 97150 for multi-patient treatment under Part B. Update your billing staff training to eliminate “concurrent therapy” terminology for outpatient Medicare patients.

Mistake 2: Billing Group Therapy While Providing One-on-One to Another Patient

The Error: Therapist provides hands-on manual therapy to one patient while two other patients exercise nearby, then bills group therapy for the exercising patients and individual codes for the manual therapy patient.

Why It’s Wrong: The therapist is not in constant attendance with the group if they’re providing one-on-one attention to a different patient. You cannot bill both simultaneously.

The Fix: Structure your schedule to separate individual and group sessions. If you must overlap, bill only for the patient receiving direct one-on-one intervention, or restructure the session so you’re truly providing skilled group intervention to all patients.

Mistake 3: Not Documenting Individualized Goals

The Error: Documentation says “Group participated in balance activities” without specifying each patient’s individual goals, performance, or response.

Why It’s Wrong: Group therapy must still address each patient’s individualized plan of care. Generic documentation suggests services weren’t medically necessary or appropriately individualized.

The Fix: Document each patient’s specific goals being addressed, their individual performance, your skilled intervention for that patient, and their progress. Proactive Chart’s documentation templates include prompts for individualized goal tracking even in group settings.

Mistake 4: Not Using Modifier 59 for Same-Day Group and Individual Sessions

The Error: Billing both 97150 (group therapy) and time-based individual codes (like 97110, 97140) on the same day without Modifier 59.

Why It’s Wrong: NCCI edits will bundle the services, and you’ll only receive payment for the lower-priced group therapy code.

The Fix: Always append Modifier 59 to one of the codes (typically the individual therapy code) to indicate distinct, separate sessions. Ensure your documentation clearly shows different timeframes and distinct interventions.

Mistake 5: Documenting Supervision Instead of Skilled Intervention

The Error: Documentation reads “Supervised patients during exercise program” or “Patients performed exercises independently with therapist oversight.”

Why It’s Wrong: Medicare explicitly states that supervision of previously taught exercises or independent exercise is not skilled service and is not covered as group therapy.

The Fix: Document the skilled therapeutic techniques you provided: cueing, manual facilitation, real-time modifications, education, clinical decision-making. If patients can exercise independently without skilled intervention, group therapy is not medically necessary.

Mistake 6: Exceeding the 25% Cap in SNF/Part A Settings

The Error: Providing more than 25% of total therapy minutes as group or concurrent therapy for SNF Part A patients.

Why It’s Wrong: Violates PDPM requirements and triggers compliance warnings.

The Fix: Track group/concurrent minutes throughout the Part A stay. Use EMR reports to monitor compliance before discharge. Plan therapy schedules to ensure at least 75% individual treatment.

Mistake 7: Incomplete Time Documentation

The Error: Not documenting total time spent in group therapy session because “it’s an untimed code.”

Why It’s Wrong: While 97150 doesn’t require 8-minute rule calculations, Medicare still expects you to document session duration to establish medical necessity and reasonable service provision.

The Fix: Always include total group therapy time in your documentation: “Patient participated in 50-minute group therapy session addressing balance and gait activities.”

Mistake 8: Billing Excessive Group Therapy Without Individual Treatment

The Error: A practice bills predominantly group therapy with minimal individual sessions, driven by scheduling convenience rather than medical necessity.

Why It’s Wrong: Creates aberrant billing patterns compared to peers, triggering Medicare audits. Group therapy should be clinically driven, not an administrative convenience.

The Fix: Ensure your therapy mix reflects patient needs. While Part B doesn’t have a formal cap, best practice suggests group therapy should complement—not replace—individual treatment. Document clinical justification when group therapy is appropriate (e.g., social interaction, peer modeling, functional environment simulation).

How EMR Software Prevents Group Therapy Billing Errors

Modern EMR systems designed specifically for rehabilitation practices include built-in safeguards that prevent common group therapy billing mistakes. Proactive Chart offers several features that ensure compliant CPT 97150 billing:

Automated Compliance Checks

Modifier validation: System prompts for Modifier 59 when billing both group and individual therapy on the same day
Therapy-type modifiers: Auto-applies GP/GO/GN modifiers based on discipline
NCCI edit warnings: Alerts you to coding combinations that will be rejected before claim submission

Smart Documentation Templates

Individualized goal prompts: Templates require documentation of each patient’s specific goals addressed during group session
Skilled intervention fields: Structured sections ensure you document skilled techniques, not just supervision
Time tracking: Captures total group session time even though 97150 is untimed

Billing Pattern Analytics

Track group vs. individual therapy ratios to identify aberrant patterns before they trigger audits
Compare your billing patterns to national benchmarks
Monitor high-risk billing behaviors (like same-day group/individual billing without modifiers)

Integrated Education and Resources

Built-in links to CMS guidance documents, billing scenarios, and compliance updates keep your team informed about the latest Medicare rules. For practices managing complex billing scenarios, understanding tools like physical therapy billing and RCM systems can significantly reduce errors and improve cash flow.

SNF/Part A Monitoring Tools

For practices serving SNF patients, Proactive Chart tracks:

Cumulative group/concurrent therapy minutes per patient per discipline
Percentage of total therapy delivered in group vs. individual mode
Automatic alerts when approaching the 25% cap
PPS discharge assessment preparation with pre-populated O0425 data

Key Takeaways: Group Therapy Billing Checklist

Before submitting claims for CPT 97150, verify:

✅ Two or more patients received treatment simultaneously ✅ Therapist was in constant attendance throughout the session ✅ Therapist was NOT providing one-on-one treatment to a different patient during the group ✅ Skilled intervention was provided (not just supervision of independent exercise) ✅ Total session time is documented in the note ✅ Each patient’s individualized goals are documented ✅ Each patient’s participation and response is documented ✅ Medical necessity is clearly established for each patient ✅ Appropriate modifiers applied (GP/GO/GN, plus CQ/CO if applicable) ✅ Modifier 59 included if billing group and individual therapy same day ✅ Documentation distinguishes separate sessions when billing same-day group and individual ✅ For SNF/Part A patients: Group/concurrent minutes do not exceed 25% cap

Conclusion: Master Group Therapy Billing for Compliance and Revenue Optimization

Group therapy under CPT 97150 offers legitimate opportunities to increase practice efficiency and serve more patients—but only when billed correctly according to Medicare’s specific rules. The critical distinctions between group and concurrent therapy, the constant attendance requirement, proper use of modifiers, and audit-proof documentation are non-negotiable compliance requirements in 2025.

As CMS continues to increase audit scrutiny and target aberrant billing patterns, practices that master these rules will not only avoid costly penalties but also optimize revenue while delivering high-quality patient care. Understanding how group therapy billing integrates with other Medicare requirements—like MIPS reporting for physical therapy—ensures comprehensive compliance across all aspects of your practice.

The most successful practices treat compliance as a competitive advantage, not just a regulatory burden. By implementing structured documentation protocols, leveraging EMR compliance tools, and continuously educating staff on the latest Medicare guidance, you can confidently bill group therapy while building an audit-resistant practice.

Remember: when in doubt, refer to the official CMS 11 Part B Billing Scenarios document and consult with qualified billing professionals. The upfront investment in getting group therapy billing right pays dividends in reduced denials, faster reimbursement, and peace of mind during audits.

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