Timed vs Untimed CPT Codes for Physical Therapy: Difference Explained

Physical therapy coding and billing are different from conventional medical billing because reimbursement often depends not only on which CPT code is reported but also on how long the therapist spends delivering skilled treatment. This is why there are two types of Physical therapy billing. Some therapy services are billed based on the time spent providing one-on-one care, while others are billed only once per session regardless of treatment duration. These are known as timed and untimed billing, and the CPT codes for physical therapy, along with the billing rules, differ for each.

According to CMS, timed therapy services require direct one-on-one patient contact, whereas untimed services are generally billed once per visit regardless of the minutes documented. Therefore, understanding the difference between the two is essential for accurate billing, Medicare compliance, and proper reimbursement. Incorrect unit calculation, misunderstanding the 8-minute rule, or reporting untimed services as timed procedures can lead to claim denials, overpayments, or compliance issues during audits.

Timed vs Untimed CPT Codes for Physical Therapy: Key Differences

The primary difference between timed and untimed CPT codes for physical therapy is how they’re billed, considering time. Let’s explore the difference between both timed and untimed CPT codes:

1. Billing Method 

 It is the biggest distinction between timed and untimed CPT codes.

Timed: These are billed in 15-minute increments, allowing providers to report multiple units based on the total skilled treatment time. 

Untimed: Billed only once per treatment session, regardless of how long the service takes.

2. Time Requirement

Timed:  The reimbursement depends on the total minutes of direct one-on-one treatment delivered by the therapist. 

Untimed: It doesn’t rely on treatment duration. As long as the service is completed and properly documented. 

3. Documentation Requirements

Timed: The required documents are: Total treatment minutes, Skilled interventions performed, Medical necessity, Patient response to treatment

Untimed CPT Codes for Physical Therapy: The documentation requirement of the service is the same, but reimbursement isn’t based on treatment minutes. 

4. Examples

Timed CPT codes: 

97110: Therapeutic Exercise

97112: Neuromuscular Reeducation

97116: Gait Training

97140: Manual Therapy

97530: Therapeutic Activities Common 

Untimed CPT codes: 

97010: Hot/Cold Packs

97012: Mechanical Traction

97161–97164: Physical Therapy Evaluations and Re-evaluations 

5. Billable Units

Timed: The providers can report one or more billable units based on the total skilled treatment time. Medicare generally applies the 8-minute rule to determine the number of units that can be billed for a service.

Untimed: Billed as one unit per completed service, regardless of how long the treatment takes. Because the reimbursement is tied to the service itself.

6. Coding Complexity

Timed: More complex to bill because providers must calculate billable units, follow Medicare’s 8-minute rule when applicable, and maintain detailed documentation for every treatment session. Even minor errors in time calculations or documentation can result in claim denials or reimbursement delays.

Untimed: These are simpler because reimbursement is not based on treatment time. However, correct CPT codes for physical therapy treatment, complete clinical documentation, and payer-specific billing guidelines must be followed to ensure accurate reimbursement and regulatory compliance.

8-Minute Rule Explained: CMS and AMA

One of the most important billing rules for timed CPT codes for physical therapy is the 8-minute rule. But when it comes to reporting scheduled treatment services, the Centres for Medicare and Medicaid Services (CMS) & the American Medical Association (AMA) have differing regulations. Healthcare providers may need to follow different rules depending on the payer. 

Let’s explore both:

According to the CMS Medicare Claims Processing Manual, providers may bill one unit of a timed service only when at least 8 minutes of direct one-on-one treatment have been provided. When multiple timed procedures are performed during the same visit, therapists should calculate the total timed treatment minutes first and then allocate billable units based on the time spent on each service. For example: 

8–22 minutes = 1 unit

23–37 minutes = 2 units

38–52 minutes = 3 units

53–67 minutes = 4 units

Many other professionals follow the American Medical Association (AMA) CPT midpoint rule. Under this methodology, a 15-minute timed CPT code for physical therapy may generally be reported once more than half of the service time has been provided.

For example, if a therapist performs 8 minutes of therapeutic exercise (97110), many commercial payers following the AMA guideline allow reporting one unit of that service. However, billing requirements vary by insurer, so practices should always verify each payer’s policy before submitting claims.

The Need for Outsourcing Medical Billing

Physical therapy coding and billing is a complex process, especially when the in-house team is already managing a heavy workload and other responsibilities. This increases the chances of billing errors, which can ultimately lead to revenue loss. That is why outsourcing medical billing services for physical therapy is essential.

An audit by the U.S. Department of Health and Human Services Office of Inspector General (OIG) found that 61% of reviewed Medicare outpatient physical therapy claims failed to comply with Medicare requirements, resulting in an estimated $367 million in improper payments. While the audit covered multiple issues, including documentation, medical necessity, and coding, it highlights the importance of accurately documenting treatment time and applying Medicare billing rules correctly.

This is why partnering with specialized medical billing services for physical therapy is essential. If your practice is facing billing challenges related to CPT codes for physical therapy, connect with AmFac Medical Management, one of the medical billing companies in the USA. Our certified billing and coding professionals help you with:

• Accurate CPT codes adhering to the latest CMS, AMA CPT, and payer guidelines.
• Verify correct unit calculations.
• Identify billing discrepancies before claims are submitted
• Proactively manage denials when they occur

This helps you maximize reimbursements while keeping your practice compliant.

Conclusion 

The common differences between timed and untimed CPT codes for physical therapy include their billing method, time requirements, documentation standards, billable unit calculation, coding complexity, and reimbursement guidelines. Understanding these differences helps physical therapy practices submit accurate claims, remain compliant with Medicare and payer requirements, and reduce billing errors that can lead to claim denials. Partnering with one of the medical billing companies in the USA, like AmFac Medical Management, can further simplify physical therapy billing, improve coding accuracy, and maximize reimbursements.