Medical emergency?Emergency? Call 911. Nearest emergency roomsNearest ERs

Internal Medicine

Lydia C. Siegel, MD

Works at hospitals in Jamaica Plain, MA · Boston, MA · Massachusetts

Summary

Dr. Lydia C. Siegel, MD is an internal medicine doctor at 640 Centre St, Boston, MA 02130. Phone: (617) 983-6039. Accepts Medicare assignment. In 2024, Lydia C. Siegel had 49 Original Medicare patients and 86 services. NPI 1003892001. Source: CMS National Downloadable File, updated October 2, 2026; CMS Facility Affiliation Data, updated October 2, 2026; CMS Medicare Physician & Other Practitioners, data year 2024.

From official Medicare data

This page shows what Medicare's official clinician data says about Lydia C. Siegel, joined by NPI number (data updated October 2, 2026). It is not a recommendation or a rating. Call the office or hospital to confirm before you go.

In a medical emergency, call 911.

Quick answers

Does Lydia C. Siegel accept Medicare assignment?
Yes. Medicare's clinician data says Lydia C. Siegel accepts Medicare assignment (the Medicare-approved amount as full payment for covered services), as of October 2, 2026. Ask the office to confirm before your visit.
How many Medicare patients does Lydia C. Siegel see?
In 2024, CMS data shows 49 Original Medicare patients and 86 services for Lydia C. Siegel. This counts Original Medicare only and measures volume, not quality.
What is Lydia C. Siegel's NPI number?
1003892001. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.

Medicare activity in 2024

Official CMS public-use data for Lydia C. 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.

Original Medicare patients49
Services billed to Medicare86
Different services or procedures7
Participating Medicare providerYes
Average age of these patients71

Most frequent services

  1. Established patient office or other outpatient visit with high level of medical decision making, if using time, 40 minutes or more (99215)32 services
  2. Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more (99214)26 services
  3. 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)20 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 pressure73%
  • High cholesterol69%
  • Arthritis63%
  • Diabetes51%
  • Anxiety41%
  • Depression39%

Hospitals where Lydia C. Siegel works

Medicare's Facility Affiliation Data lists Lydia C. 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.

Practice locations

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

Group practices

Medicare enrollment lists Lydia C. Siegel as a member of this group (CMS data updated October 2, 2026).

  • Brigham and Womens Hospital Inc52 clinicians in the group

Specialties

Find other Internal Medicine doctors in Massachusetts →

Other internal medicine doctors in Boston

Clinicians with the same Medicare primary specialty in Boston, MA — not a recommendation.

All internal medicine doctors in Boston →

Other clinicians in Brigham and Womens Hospital Inc

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

Clinician information

CredentialMD
Graduation year2003 (23 years since medical school)
Gender (as listed)Female
Medicare assignmentAccepts (Medicare-approved amount as full payment)
NPI (National Provider Identifier)1003892001
CorrectionsReport an error or suggest an update →

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