When submitting a claim for payment, it is important to bill the correct amount of units. Entering the CPT or HCPCS procedure code that identifies the service provided is the first step. However, in many cases, a procedure or supply has a specified number of units as part of the definition of the code. It is important to correctly report the units within the guidelines for the code as well as the requirements of the payer.

The following are some important considerations when billing units:

• If the same procedure is provided multiple times on the same date of service, enter the procedure only once. Then use the units field to appropriate indicate the number of times the service was provided.
• It is appropriate to indicate a date range and then enter the number of times the service was provided during the specified time frame.
• Pay attention to the definition which may include references to time (e.g., 15 minutes), size (e.g., 2 centimeters), or even weight (e.g., 2 CC). These should be accounted for when calculating the appropriate number of units.
• Be aware of payer's maximum number of units. Not all codes have them, but some do. CMS's guidelines are published as their Medically Unlikely Edits (MUEs). These can be viewed by subscription on FindACode.com.
• In some cases, payers do not accept claims with units of less than one. Be aware of payer policies.

The following tips are from a CMS 1500 Claim Form fact sheet by CMS: 

• Ensure that the number of units/days and the date of service range are not contradictory.
• Ensure that the number of units/days and the quantity indicated in the procedure code’s description are not contradictory. 

Many payers follow Medicare's lead when it comes to billing policies. The "Medicare Claims Processing Manual" states the following:

B. Timed and Untimed Codes

When reporting service units for HCPCS codes where the procedure is not defined by a specific timeframe (“untimed” HCPCS), the provider enters “1” in the field labeled units. For untimed codes, units are reported based on the number of times the procedure is performed, as described in the HCPCS code definition (often once per day).

EXAMPLE: A beneficiary received a speech-language pathology evaluation represented by HCPCS “untimed” code 92521. Regardless of the number of minutes spent providing this service only one unit of service is appropriately billed on the same day.

Several CPT codes used for therapy modalities, procedures, and tests and measurements specify that the direct (one on one) time spent in patient contact is 15 minutes. Providers report procedure codes for services delivered on any single calendar day using CPT codes and the appropriate number of 15 minute units of service.

EXAMPLE: A beneficiary received occupational therapy (HCPCS “timed” code 97530 which is defined in 15 minute units) for a total of 60 minutes. The provider would then report revenue code 043X and 4 units.

Other Important Information

Correctly reporting units can vary depending on payer guidelines. Providers need to understand other problem areas and guidelines to ensure they are billing units properly. The following articles provide additional guidance:

• Billing of drugs and biologicals, timed codes, and multiple injections
• Medicare: Counting Minutes for Timed Codes in 15 minutes