Marc O. Siegel, MD

Medicare activity in 2024

Official CMS public-use data for Marc O. Siegel, data year 2024 (released May 21, 2026). It covers Original Medicare (fee-for-service) patients only, not Medicare Advantage or other insurance. It shows volume, not quality or outcomes. CMS hides any count of 10 or fewer patients.

Most frequent services

1. Subsequent hospital care with moderate levelof medical decision making, if using time, at least 35 minutes (99232)172 services
2. Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more (99214)107 services
3. Initial hospital care with straightforward or low-level medical decision making, if using time, at least 55 minutes (99222)79 services
4. Visit complexity inherent to evaluation and management associated with medical care services that serve as the continuing focal point for all needed health care services and/or with medical care services that are part of ongoing care related to a patient's (G2211)54 services
5. Subsequent hospital care with straightforward or low level of medical decision making, per day, if using time, at least 25 minutes (99231)28 services

Chronic conditions among these patients

Share of this clinician’s Original Medicare patients with each condition, as published by CMS (it describes the patients, not the care given).

• High blood pressure75%
• High cholesterol75%
• Arthritis59%
• Ischemic heart disease54%
• Diabetes49%
• Chronic kidney disease48%

Hospitals where Marc O. Siegel works

Medicare's Facility Affiliation Data lists Marc O. Siegel at these hospitals (updated October 2, 2026). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians. Star rating and emergency services: Hospital General Information (CMS), data updated October 26, 2026.

• George Washington University HospitalWashington, DC · Acute Care Hospital · Medicare rating: 2 of 5 stars · Emergency services: listed by Medicare · CCN 090001

Practice locations

Addresses where Marc O. Siegel is enrolled with Medicare (CMS data updated October 2, 2026).

• 1525 14th St NWWashington, DC 20005 (202) 745‑7000
• 2150 Pennsylvania Ave NWWashington, DC 20037 (202) 741‑2600
• 900 23rd St NWWashington, DC 20037 (202) 715‑4000

Group practices

Medicare enrollment lists Marc O. Siegel as a member of these groups (CMS data updated October 2, 2026).

• Medical Faculty Associates, Inc672 clinicians in the group
• Whitman-Walker Clinic, Inc.62 clinicians in the group

Specialties

• Infectious Diseaseprimary

Find other Infectious Disease doctors in District of Columbia →

Other infectious disease doctors in Washington

Clinicians with the same Medicare primary specialty in Washington, DC — not a recommendation.

• Adam Klein, DO
• Matthew J. Copeland, DO
• Seble Kassaye, MD
• Gayle Balba, MD
• Princy N. Kumar, MD
• Jesse L. Goodman, MD
• Robert A. Delapenha, MD
• Andrea Hulse, MD

All infectious disease doctors in Washington →

Other clinicians in Medical Faculty Associates, Inc

Medicare enrollment lists these clinicians in the same group practice — not a recommendation.

• Adam Thompson-Harvey, MD
• Tahira I. Lodhi, MD
• Amir Afkhami, MD
• Kevin C. O'Connor, DO
• Jane Wu, PA
• Amanda J. Miller, MD

Clinician information

Most corrections must be made at the source: clinicians update their NPI Registry record (NPPES) and their Medicare enrollment (PECOS); this page follows the next data release.

Sources

1. Facility Affiliation Data — Centers for Medicare & Medicaid Services (CMS), data updated October 2, 2026, retrieved October 29, 2026
2. Hospital General Information — CMS, data updated October 26, 2026, retrieved November 13, 2026
3. National Downloadable File (Doctors and Clinicians) — CMS, data updated October 2, 2026, retrieved October 29, 2026
4. Medicare Physician & Other Practitioners - by Provider — CMS, data year 2024, released May 21, 2026; Medicare Physician & Other Practitioners - by Provider and Service
5. NPI Registry — U.S. Department of Health and Human Services (NPPES), the clinician’s official record
6. Medicare Care Compare — official Medicare tool to look up clinicians