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Clarice Grote, MS, OTR/L

Clarice Grote, MS, OTR/L

How To Bill Occupational Therapy Under Medicare Part B

Medicare Part B is utilized in acute care, long-term care, outpatient, and Med B home health services. Billing occupational therapy under Medicare Part B can be complex as the responsibility to document and bill correctly typically falls on the clinician.

For those working under their own National Provider Identifier (NPI), accurate coding is even more important. If practitioners do not have a thorough understanding of how to bill Medicare, it could mean losing your license or underbilling for needed services.

Medicare Part B is billed through CPT codes in a fee-for-service model. Practitioners cannot bill cash for covered services for Medicare beneficiaries. Without a supplemental plan, beneficiaries will have a 20% copay for Part B services.

When looking for accurate information on billing and coverage, going directly to the source is important. The Medicare Benefit Policy Manual for Part B Services provides details on the type of services covered under Medicare Part B for Occupational Therapy. Chapter 15

Questions about Billing Medicare Part B?

Amplify OT and AOTA’s Regulatory Affairs Team is here to help! You can reach them at Keep in mind you must be a member of AOTA to receive a response to inquiries due to a high volume of messages.

Merit-Based Incentive Payment System (MIPS)

Never heard of MIPS? Check out the information in the link below to see if you or your clinic needs to be reporting to MIPS. OTs are eligible to opt-in even if not required to report to MIPS. –> AOTA Resources

Coding and Billing for Occupational Therapy Under Medicare Part B

AOTA’s Coding and Billing Page has numerous resources for members and non-members. The videos on billing are beneficial and easy to understand.

Evaluation Codes

Eval codes are used during the first visit. They are coded as low, medium, or high complexity based on patient factors. Although there are times associated with the description of each code, these are just guidelines and do not have to reflect the actual time spent on the evaluation.

Evaluation codes are untimed codes, so you receive the same amount of reimbursement regardless of if you bill eight minutes in the eval or 30. That said, legally, your billed time must accurately represent the time spent on the evaluation and subjective interviewing of the patient.

Evaluation typically consists of manual muscle testing, range of motion measurements, assessments, subjective interviewing, etc. Once you transition to education or prescribing exercises/activities, that is treatment vs evalutation. Knowing exactly when this transition occurs relies on the clinician’s clinical judgement.

During an eval can, and should, bill treatment codes with the evaluation. This time should be charged under treatment codes that fall under the 8-minute rule. Consider, how would you feel if you went to the doctor and all they did was evaluate you but not prescribe any treatment or provide education about the diagnosis? It should be rare only to charge an evaluation code.

Timed Codes

The 8-Minute Rule is used for timed CPT codes. Billable time must be spent face-to-face with the patient. You must provide a skilled, reimbursable service that fits within the CPT code description.

Time spent before or after the session, such as chart reviews, interdisciplinary collaboration, or documentation, cannot be billed.

To charge a timed code, a minimum of 8 minutes of one-on-one, face-to-face care must be provided. There is then a 15-minute window between each unit of service, as demonstrated in the table below.

1 Unit8-22 minutes
2 Units23 – 37 minutes
3 Units38-52 minutes
4 Units53 – 67 minutes
5 Units68 – 82 minutes
Timed Code Unit Breakdown


OTA Modifier

As of January 2020, CMS required a modifier to indicate an occupational therapy assistant provided the services. This change was required as part of the Balanced Budget Act (BBA) of 2018. The use of the modifier is preparatory for a 15% reduction in reimbursement for services provided by OTAs starting January 1, 2022. AOTA is actively lobbying Congress to change the reduction and add exemptions for rural areas.

Read more HERE

KX Modifier

The KX Modifier is utilized to indicate medical necessity, specifically for services over the therapy threshold. The threshold is typically updated annually so be sure to check Medicare guidelines each year. For 2021, the therapy threshold is $2110 for occupational therapy and $2110 for physical and speech therapy services.

Services provided over $3000 for the calendar year may be subject to a targeted medical review. This means that not all claims will be reviewed, however, if you consistently bill over the threshold, your chances of being reviewed may increase. The purpose of the targeted review is to prevent bad actors from billing for unnecessary services. There is not a hard cap on therapy services.

Of note, it is important to document medical necessity for therapy services in each note, not only when utilizing the KX modifier. Any claim may be denied for various reasons. Not just those above the threshold.

Diagnostic Coding


For example, if the patient’s diagnostic code is for a CVA, but does not include a code for left upper extremity hemiplegia, you can still use this code. The diagnostic code should reflect the patient’s diagnosis and the plan of care.

So, if you use generalized weakness as your therapy code, CMS would expect that your plan of care will address weakness.

Therapy Diagnostic Coding – ICD-10 Coding Resources

Other Resources

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