Rule of 8's
The CPT® Rule of 8’s works with the Medicare 8-Minute Rule to calculate the number of allowed units for timed codes. While the 8-Minute Rule is automatically applied and cannot be changed, the Rule of 8's is an optional setting that can be applied to non-Medicare insurance types. To learn more about how the 8-Minute Rule works with the Rule of 8's, click here.
Remember: These rules are only applied to Direct-Timed Codes.
The Rule of 8’s follow the same principles as the 8-Minute Rule and is calculated on a per-service basis. This rule applies to timed codes that have 15 minutes as the “usual time” in the operational definition of the code. You must perform half the service time described in a timed code before you can bill 1 unit of that code; therefore, at least 8 minutes of a unique service must be performed in order to bill one unit of that service.
Time-based CPT Codes
Time-based (or constant attendance) codes allow for variable billing in 15-minute increments. You would use these codes for performing one-on-one services such as:
- therapeutic exercise (97110)
- therapeutic activities (97530)
- manual therapy (97140)
- neuromuscular re-education (97112)
- gait training (97116)
- ultrasound (97035)
- iontophoresis (97033)
- electrical stimulation (manual) (97032)
The Rule of 8's is applied to each timed service separately, so the math is also applied separately:
1 unit of a unique service = at least 8 minutes of a service are needed for each unique service billed
- 10 minutes of 97110 in a single visit = 1 unit
- 10 minutes of 97110 AND 10 minutes of 97116 in a single visit = 2 units total [1 unit of 97110 and 1 unit of 97116 because I have the minimum 8 minutes for each service]
2 units of a unique service = at least 23 minutes for that unique service
- 25 minutes of 97110 in a single visit = 2 units
- 25 minutes of 97110 AND 10 minutes of 97116 in a single visit = 3 units total [2 units of 97110 because I have the minimum of 23 minutes and 1 unit of 97116 because I have the minimum of 8 minutes]
Insurance Manager Setup
- From the Insurance Manager, select the Display Insurance link.
- Search for the insurance to apply the CPT® Rule of 8’s settings. Use the Edit link to open the Edit Insurance window.
- In the Edit Insurance screen, check Apply the CPT® Rule of 8’s.
- Select Edit Insurance to save.
- This process is the same when using the Add Insurance link from the Insurance Manager.
Once the setting is turned on, you will be required to document minutes of service in the Charge Summary section of the SOAP note.
An alert will appear if you are under or overbilling. You will be required to correct your billing before finalizing the note.