CPR’s “Coding Corner” focuses on coding, compliance and documentation issues relating specifically to physician billing. This month’s tip comes from G. John Verhovshek, the managing editor for AAPC, a training and credentialing association for the business side of health care.

Unless otherwise indicated in the CPT® codebook, five rules govern reporting for time-based CPT® services.

1. Time must be face-to-face
Time away from the patient is billable only if the code descriptor or other CPT® guidelines specifically allow for it. For example, prolonged services without direct patient contact (99358-99359) does not describe face-to-face time with the patient.

“Face-to-face” services may allow you to count some non face-to-face time. For example, critical care (99291-99292) includes “time spent on the unit or at the nursing station on the floor reviewing test results or imaging studies, discussing the critically ill patient’s care with other medical staff or documenting critical care services in the medical record.”

2. A unit of time is attained when the mid-point is passed
If a code describes the “first hour” of service, you must provide and document at least 31 minutes of service; if the unit of service is 30 minutes, at least 16 minutes must be documented; and so on. If the minimum time to report is not met, either the service is not billable, or you should report an(other) appropriate E/M service code. For example, if fewer than 30 minutes of critical care (99291) are provided, CPT® instructs you to report “appropriate E/M codes.”

Some codes describe “24-hour services.” Generally, at least 12 hours of service must be documented to report the code. For services lasting fewer than 12 hours, you may need to append modifier 52 Reduced services.

Bonus tip: As a best practice, physicians providing time-based services should report the total time of service, and start and stop times.

3. Select the “closest” time-based code
CPT® states, “When codes are ranked in sequential typical times and the actual time is between to typical times, the code with the typical time closest to the actual time is used.”

This rule applies when reporting E/M services using time (rather than the key components of history, exam and medical decision-making) as the determining factor in the level of service. In such cases, use CPT® “reference times” to determine an appropriate E/M service level. For example, a level III established patient outpatient visit (99213) has a reference time of 15 minutes, while a level IV service (99214) has a reference time of 25 minutes. When reporting a time-based E/M lasting 19 minutes, you would code 99213.

4. Don’t combine unrelated services
Do not count the time of an unrelated service when reporting a time-based service. For example, time spent providing separately reportable procedures or services should not be included toward critical care time (99291, 99292).

What counts as “time” varies by service. For instance, critical care includes floor/unit time in addition to time spent at a patient’s bedside, while other time-based services (such as standby services) do follow different rules. Study CPT® guidelines and descriptors to learn what counts as “time” for a given service.

5. For continuous services, the date of service doesn’t change
Per CPT®, “For continuous services that last beyond midnight, use the date in which the service began and report the total units of time provided continuously.”

For instance, if intravenous hydration begins at 10:30 p.m. and lasts until 1:30 a.m. the next calendar day, you would report 96360 Intravenous infusion, hydration; initial, 31 minutes to 1 hour once and 96361 …each additional hour (List separately in addition to code for primary procedure) twice.