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

Endocrinology

Gary D. Hammer, MD

Works at hospitals in Ann Arbor, MI · Michigan

Summary

Gary D. Hammer, MD (Endocrinology) is listed by Medicare at 1 hospital in Ann Arbor, MI. NPI 1871676791. Medicare data says the clinician accepts Medicare assignment. Source: CMS Facility Affiliation Data, updated 2026-10-02.

From official Medicare data

This page shows what Medicare's official clinician data says about Gary D. Hammer, joined by NPI number (data updated 2026-10-02). It is not a recommendation or a rating. Call the office or hospital to confirm before you go.

In a medical emergency, call 911.

At a glance

EndocrinologyPrimary specialty
YesAccepts Medicare assignment
34Years since medical school (graduated 1992)
Tufts University School Of MedicineMedical school
MaleGender (as listed)
Regents of the University of MichiganGroup practice

Quick answers

Which hospitals does Gary D. Hammer work at?
Medicare's official clinician data lists Gary D. Hammer at 1 hospital: University of Michigan Health System. This is where the clinician works or has privileges; call the hospital to confirm.
Where does Gary D. Hammer see patients?
Medicare's clinician data lists 12 practice locations, including Ann Arbor, MI. Call before your visit to confirm the address.
What is Gary D. Hammer's specialty?
Medicare lists Endocrinology as the primary specialty, and also Internal Medicine.
Does Gary D. Hammer accept Medicare assignment?
Yes. Medicare's clinician data says Gary D. Hammer accepts Medicare assignment (the Medicare-approved amount as full payment for covered services), as of 2026-10-02. Ask the office to confirm before your visit.
What is the phone number for Gary D. Hammer?
(734) 936-5738, as listed in official Medicare / NPI Registry data.
What is Gary D. Hammer's NPI number?
1871676791. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.

Hospitals where Gary D. Hammer works

Medicare's Facility Affiliation Data lists Gary D. Hammer at these hospitals (updated 2026-10-02). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians.

Practice locations

Addresses where Gary D. Hammer is enrolled with Medicare (CMS data updated 2026-10-02). The first 5 of 12; the Medicare profile lists all.

Group practices

Medicare enrollment lists Gary D. Hammer as a member of this group (CMS data updated 2026-10-02).

  • Regents of the University of Michigan3,346 clinicians in the group

Specialties

Find other Endocrinology doctors in Michigan →

Other endocrinologists in Ann Arbor

Clinicians with the same Medicare primary specialty in Ann Arbor, MI — not a recommendation.

All endocrinologists in Ann Arbor →

Clinician information

CredentialMD
Medical schoolTufts University School Of Medicine
Graduation year1992
Gender (as listed)Male
Medicare assignmentAccepts (Medicare-approved amount as full payment)
NPI (National Provider Identifier)1871676791
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 2026-10-02, retrieved 2026-10-29
  2. National Downloadable File (Doctors and Clinicians) — CMS, data updated 2026-10-02, retrieved 2026-10-29
  3. NPI Registry — U.S. Department of Health and Human Services (NPPES), the clinician’s official record
  4. Medicare Care Compare — official Medicare tool to look up clinicians