G0545 – The New Complexity Code for Infectious Disease Specialists

The 2025 Medicare Physician Fee Schedule (PFS) Final Rule released a new complexity add-on HCPCS code. Although this code has similarities to the G2211 complexity add on code, it has significant restrictions on who can submit claims for its use. The new code, G0545, is a code that is for use by “a physician with specialized training in infectious diseases.” The new code descriptor provides: 

G0545 - Visit complexity inherent to hospital inpatient or observation care associated with a confirmed or suspected infectious disease by an infectious diseases specialist, including disease transmission risk assessment and mitigation, public health investigation, analysis, and testing, and/or complex antimicrobial therapy counseling and treatment (add-on code, list separately in addition to hospital inpatient or observation evaluation and management visit, initial, same day discharge, subsequent or discharge).

The PFS Final rule clarifies that this code is “Not intended to indicate an assumption about the level of medical decision making with diagnosing and managing suspected, unknown or emerging infectious diseases.” It is intended to reflect the visit complexity inherent to care in the hospital inpatient or observation area, associated with a confirmed or suspected infections disease diagnosis.  

In finalizing this code, CMS looked at comments dating back to the CY2022 PFS Final rule along with other feedback. As a result, the following proposed service elements were listed in the 2025 PFS Final Rule indicating that the G0545 code may be assigned if one or any combination of the following elements listed are used:

1. Disease Transmission Risk Assessment and Mitigation

• Developing, following, and supervising specialized, individualized infection control protocols for an individual patient based on their diagnosis and risks in order to reduce risk of disease transmission.
• Coordinating with human resources regarding infection prevention and control measures to enable healthcare facility staff to safely care for patients.
• Counseling patients, family members and caregivers regarding infection prevention.
• Managing infection prevention and treatment protocols associated with transitions of care for complex patients.

2. Public Health Investigation, Analysis, and Testing

• In-depth patient chart review that entails going back farther in time and assessing the complete breadth of all health care interactions, with higher-level synthesis for complex diagnoses.
• Communicating with the clinical microbiology lab and directly reviewing specimens.
• Coordinating specialized diagnostic evaluations (for example, identifying and facilitating diagnostic laboratory tests only available at specialized laboratories, the state health department, and/or the Centers for Disease Control & Prevention).
• Coordinating with federal, state, and local public health agencies and laboratories to assist with contact tracing, obtaining specimens for specialized testing, and/or identifying prior testing and treatment for communicable diseases in other jurisdictions.

3. Complex Antimicrobial Therapy Counseling and Treatment

• Counseling patients, family members, and caregivers regarding antimicrobial stewardship and resistance for the patient.
• Engaging in complex medical decision-making associated with antimicrobial prescribing including considerations such as antimicrobial resistance patterns, emergence of new variants/strains, recent antibiotic exposure, interactions/complications from comorbidities including concurrent infections, public health considerations to minimize development of antimicrobial resistance, and emerging and re-emerging infections.

Further indications from the 2025 PFS Final rule clarify that the G0545 code is not intended to be a time-based code. It was felt that infectious disease specialists would be most likely be reporting their visits with the hospital inpatient or observation codes and not with office and other outpatient service codes. As such, it was shown in the final rule, as an add on code to be used in conjunction with codes 99221-99223, 99231-99233, 99234-99235, 99238-99239.

The PFS rule also noted was that there were no additional documentation requirements. Just as was seen with the G2211 complexity code, CMS indicated, “information included in the medical record or in the claims history for a patient/practitioner combination, such as diagnoses, the practitioner’s assessment and medical plan of care and/or other codes reported could serve as supporting documentation.”

This code has a facility listing of 1.33 total RVUs so using this complexity code has financial advantages. The point to remember is that it is ONLY for use by Infectious Disease Physicians, as shown by their specialty denotation, who have a confirmed or suspected infections disease diagnosis, and are in the hospital inpatient or outpatient departments. Physicians who are not infectious disease specialists but are taking care of patients with a confirmed or suspected infectious disease diagnosis are NOT able to receive payment for this code.