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How to use CPT code 99051

Learn how to properly use CPT code 99051 for sessions outside of a traditional weekday schedule.

July 14, 2025

6 min read

If you accept insurance as a therapist, then you’re familiar with the process of filing claims to payers. Proper documentation — including choosing the right CPT code — is an important part of billing insurance and will ensure you get reimbursed for your work as quickly as possible.

Add-on codes, such as CPT code 99051, can be used in addition to psychotherapy codes in certain scenarios. But before you file claims to insurance payers, it’s important to understand how this code works and when you can use it. 

Below, learn more about how to use CPT code 99051 in your therapy practice.

What is CPT code 99051?

CPT code 99051 is used for “services provided in the office during regularly scheduled evening, weekend, or holiday office hours, in addition to basic service.” 

If you work one day a week seeing clients until 9 PM, or you regularly see clients on Saturdays, you could use CPT code 99051 to reflect the time worked outside of a traditional weekday schedule. Any licensed mental health provider can use CPT code 99051, as long as it’s paired with another standalone code.

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What’s the difference between codes 99051 and 99050?

Both 99051 and 99050 represent work that occurs outside of a typical weekday schedule.

CPT code 99051 is used for services provided outside of standard business hours — such as on a weekend or week day evening — that are part of your typical schedule. For example, if you work every Tuesday night seeing clients until 8 PM, you may use code 99051 for those client sessions. What’s important is that the billed time is part of a recurring schedule. 

CPT code 99050, on the other hand, is used for services provided outside of regularly scheduled business hours. For example, if you typically work 9-5 Monday through Friday, and you meet with a client at 7 PM on Thursday, you could use this CPT code. 

What reimbursement rate can you expect when billing code 99051?

CPT code 99051 is used to reflect the inconvenience or extra work involved with working outside of standard business hours — even if said hours are part of your typical schedule as a therapist. Reimbursement rates depend on your contracts with insurance payers, so if you’re not sure, it’s best to review your contract. In any case, proper documentation is essential for justifying any code you use.

Please note this article is intended for educational purposes only. Headway doesn't support billing 99051 at this time.

When is CPT code 99051 not covered?

CPT code 99051 is typically not covered by Medicare plans (though some Medicare Advantage plans may reimburse this code). The code is also not covered if it’s not paired with a standalone code for psychotherapy or other services.

More CPT code resources

Navigating CPT codes can be challenging and time-consuming. To learn more about coding as a therapy provider, visit Headway’s library of resources, including: 

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Headway takes the guesswork out of CPT codes, modifiers, and payer-specific requirements, so you can focus on your clients instead of combing through documentation or chasing claims. Whether you're billing for individual therapy, E/M codes, or complex diagnoses, Headway ensures you're using the correct codes and getting reimbursed faster.

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This content is for general informational and educational purposes only and does not constitute clinical, legal, financial, or professional advice. All decisions should be made at the discretion of the individual or organization, in consultation with qualified clinical, legal, or other appropriate professionals.

© 2026 Therapymatch, Inc. dba Headway. All rights reserved. No part of this publication may be reproduced without permission.

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