99359 Prolong serv without contact add
Also known as: prolonged service additional office, extended service add-on, prolonged add-on
Prolonged evaluation and management service in the office or other outpatient setting requiring direct patient contact beyond the usual service; each additional 30 minutes of service after the first hour.
In Plain Language
Additional extended visit time; Extra office appointment time
Clinical Context
Used to report each additional 30-minute increment of prolonged direct patient contact in outpatient settings beyond the first hour of prolonged service.
RVU Breakdown
| Work RVU | 0.75 |
| Total RVU | 0.75 |
Est. Medicare Payment
National estimate based on 2026 CMS PFS Conversion Factor ($33.40). Actual payment varies by locality (GPCI adjustment).
Billing & Documentation
E&M codes require documentation of medical decision-making (MDM) complexity or total time spent on the encounter. For 2026, time-based coding includes all physician time on the date of the encounter.
How This Code Compares
With a work RVU of 0.75, this code ranks in the 18th percentile among Evaluation & Management codes — 2.1x below the median (1.54). The highest wRVU in this category is 18.46.
Specialties
Frequently Asked Questions
What is CPT code 99359?
CPT 99359 (Prolong serv without contact add) is a Evaluation & Management code. Prolonged evaluation and management service in the office or other outpatient setting requiring direct patient contact beyond the usual service; each additional 30 minutes of service after the first hour.
Who uses CPT code 99359?
CPT 99359 is used by All Specialties. Used to report each additional 30-minute increment of prolonged direct patient contact in outpatient settings beyond the first hour of prolonged service.
When is CPT 99359 used?
Used to report each additional 30-minute increment of prolonged direct patient contact in outpatient settings beyond the first hour of prolonged service.
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CPT® is a registered trademark of the American Medical Association. Data sourced from CMS Physician Fee Schedule RVU26A. Descriptions, synonyms, and clinical context are original content by RVU Edge.