Margaret M. Shaffer, MD

Medicare activity in 2024

Official CMS public-use data for Margaret M. Shaffer, 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. Pathology examination of tissue using a microscope, intermediate complexity (88305)946 services
2. Special stained specimen slides to examine tissue, each additional procedure (88341)360 services
3. Evaluation of fine needle aspirate with interpretation and report (88173)216 services
4. Pathology examination of tissue using a microscope, moderately high complexity (88307)202 services
5. Special stained specimen slides to examine tissue, initial procedure (88342)163 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 cholesterol75%
• High blood pressure70%
• Arthritis57%
• Cancer (breast, colorectal, lung, prostate, endometrial or leukemia/lymphoma)38%
• Ischemic heart disease26%
• Diabetes24%

Hospitals where Margaret M. Shaffer works

Medicare's Facility Affiliation Data lists Margaret M. Shaffer 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.

• Sibley Memorial HospitalWashington, DC · Acute Care Hospital · Medicare rating: 5 of 5 stars · Emergency services: listed by Medicare · CCN 090005

Practice locations

Addresses where Margaret M. Shaffer is enrolled with Medicare (CMS data updated October 2, 2026).

• 5255 Loughboro Rd NW, Sibley Memorial HospWashington, DC 20016 (202) 537‑4000
• 600 N Wolf StBaltimore, MD 21287 (410) 955‑5000

Group practices

Medicare enrollment lists Margaret M. Shaffer as a member of these groups (CMS data updated October 2, 2026).

• Johns Hopkins University2,909 clinicians in the group
• Johns Hopkins University713 clinicians in the group

Specialties

• Pathologyprimary

Find other Pathology doctors in District of Columbia →

Other pathologists in Washington

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

• Alvaro Frometa, MD
• Tapan M. Bhavsar, MD
• Andrea Richardson, MD
• Mariette Asare, MD
• Antoun Toubaji, MD
• Shabnam Samankan, MD
• Deepty Bhansali, MD
• Marissa White, MD

All pathologists in Washington →

Other clinicians in Johns Hopkins University

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

• Palmtama Grier, NP
• Lea Moujaes, MD
• Jennifer S. Mammen, MD
• Kimberly L. Levinson, MD
• Charles Arthur, MD
• Brian Cheng, 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