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2023 Changes to Prolonged Services Coding

Here's what you need to know for the new year.

December 2022

By Rupal Trivedi, Senior Manager, Physician Services

The AMA’s CPT manual has made significant changes to the prolonged service codes within the Evaluation and Management (E/M) services section of the book.

Please note, the inpatient prolonged care codes 99354 - 99357 have been deleted as of Jan 1, 2023 and have been replaced by CPT add on code + 99418.

+99418: Prolonged inpatient or observation evaluation and management service[s] time with or without direct patient contact beyond the required time of the primary service when the primary service level has been selected using total time, each 15 minutes of total time.(List separately in addition to the code of the inpatient and observation Evaluation and Management service)


  • Use in 99418 in conjunction with 99223, 99233, 99236, 99255, 99306, 99310
  • Do not report 99418 on the same date of service as 90833, 90836, 90838, 99358, 99359
  • Do not report 99418 for any time unit less than 15 minutes
  • +G0316 (prolonged hospital inpatient or observation services) is used with the primary code is 99223, 99233, 99236, or 99255.
  • +G0317 (prolonged nursing facility services) is used when the primary code is 99306 or 99310.
  • +G0318 (prolonged home or residence services) is used when the primary code is 99345 or 99350.
    • CPT Code 99223 75 minutes
    • CPT Code 99418 15 minutes Total Time 90 minutes (Report CPT codes 99223 + 99418)

CMS and AMA rules do not agree with each other since Medicare now has three different add-on codes:

  • The following HCPCS codes +G0316/+G0317/+G0318 should be reported for prolonged services on the date of an inpatient/observation visit, nursing facility service or home/residence services. Bear in mind that the selection of the right code is based on the primary code and the time requirements being met.

AMA and CMS are operating on a slightly different time scale

For AMA, the time for supporting units of the CPT’s add-on codes begins immediately after the maximum time is met for the primary code.

CPT Code 99418 Reporting Example

Here is the difference for Medicare: time for supporting units does not begin until a full 15-minute period after the maximum time is met for the primary code.

HCPCS Code G031X Reporting Example

  • CPT Code 99223 75 minutes Prolonged Service period begins at 90 minutes (75 minutes for 99223 plus 15 minutes)
  • HCPCS Code G031X 15 minutes Total
  • Time 105 minutes (Report CPT code 99223 + HCPCS code G031X)

Another revision to pay attention to: Codes 99358/99359

CPT® is keeping non-face-to-face prolonged care codes 99358 and 99359. These codes are for services performed on a date other than a face-to-face visit and they cannot be included with other care management services.

In addition, CMS, will be giving codes 99358 and 99359 a status indicator of invalid, which would make them non-payable for Medicare patients.


  • Create a chart or a table that covers CPT and HCPCS codes along with their time thresholds
  • Educate providers and remind them on following best-practice documentation to ensure time documentation
  • Conducting routine internal audits

If you need any assistance with planning for or the implementation of the 2023 changes, please reach out to our office at 609-918-0990 to Rupal Trivedi or one of our coding experts. 

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