DR. WILLIAM HEMSLEY MERWIN III M.D.
NPI 1043697600
Student in an Organized Health Care Education/Training Program in Baltimore, MD
About Dr. William Hemsley Merwin Iii M.d. NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
DR. WILLIAM HEMSLEY MERWIN III M.D. (NPI 1043697600) is an individual student in an organized health care education/training program in Baltimore, Maryland and active in the NPI registry since May 2015. He is enrolled in Medicare PECOS, is affiliated with Johns Hopkins Hospital, The, and is a graduate of Georgetown University School Of Medicine (2015).
NPPES Registry Identity
Specialties & Licenses 2
Medicare Participation & PECOS CMS
Medicare enrollment, assignment, billing reassignment, and ordering and referring status from CMS.
Medicare Enrollment Status
Enrolled in Medicare and accepts Medicare assignment
Dr. William Hemsley Merwin Iii M.d. is registered in PECOS and agrees to accept the Medicare-approved amount as full payment. Medicare patients are not billed beyond the standard deductible and coinsurance.
Medicare Billing Reassignment
Medicare enrollment records show William Merwin reassigns Medicare billing to 1 organization. The organization bills Medicare for the services this provider delivers there.
Baltimore, MD 21239
- Reassigned Medicare billing, District of Columbia and Maryland enrollments
- 3,530 clinicians in this Medicare group
Source: CMS Revalidation Reassignment List, October 2026 release. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.
Hospital Affiliations CMS Care Compare 2
Hospitals where this provider delivers care, identified from recent Medicare claims and place-of-service records.
Johns Hopkins Hospital, The
Acute Care Hospitals · Baltimore, MDMedstar Franklin Square Medical Center
Acute Care Hospitals · Rosedale, MDReferred Medical Equipment & Supplies CMS DME claims 2
Durable medical equipment, devices and supplies this provider ordered from DME suppliers for patients, from Medicare fee-for-service claims.
Other Providers at the Same Location NPPES 20
Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.
BALTIMORE, MD 21218
BALTIMORE, MD 21218
BALTIMORE, MD 21218
BALTIMORE, MD 21218
BALTIMORE, MD 21218
BALTIMORE, MD 21218
Frequently Asked Questions NPPES & CMS
Common questions about this NPI record, answered from the official NPPES registry and CMS datasets shown on this page.
What is William Merwin's NPI number?
The NPI number for William Merwin is 1043697600. It was assigned to this individual provider in the NPPES registry on May 4, 2015.
Where is William Merwin located?
William Merwin practices at 201 E University Pkwy Dept Of, Baltimore, MD 21218. The listed phone number is (410) 554-2284.
What is William Merwin's specialty?
The primary specialty registered for this NPI is Student in an Organized Health Care Education/Training Program with taxonomy code 390200000X.
Is William Merwin enrolled in Medicare?
Yes. William Merwin is registered in the Medicare PECOS system and accepts Medicare assignment, which means accepting the Medicare-approved amount as payment in full for covered services.
Which organization bills Medicare for William Merwin's services?
According to the CMS Revalidation Reassignment List (October 2026 release), William Merwin reassigns Medicare benefits to Medstar Medical Group II LLC (Baltimore, MD). The reassignment is filed with Medicare on form CMS-855R, signed by both the clinician and the organization, and lets the organization bill Medicare and receive payment for William Merwin's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.
Is William Merwin affiliated with any hospitals?
According to CMS data, William Merwin is affiliated with Johns Hopkins Hospital, The and Medstar Franklin Square Medical Center.
When was this NPI record last updated?
The NPPES record for William Merwin was last updated on June 11, 2025. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 16 months ago. If this record has changed at CMS more recently, you can request an on-demand re-check against the live CMS registry, directly from this page.
# Dr. William Hemsley Merwin III, M.D. · NPI 1043697600
Student in an Organized Health Care Education/Training Program provider in Baltimore, Maryland. Individual provider, active in the CMS NPPES registry since May 4, 2015.
## Identity
- **NPI:** 1043697600 (Entity type: Individual)
- **Enumerated:** May 4, 2015
- **Primary specialty:** Student in an Organized Health Care Education/Training Program · taxonomy 390200000X
- **Sole proprietor:** Yes
## Practice location
- **Address:** 201 E UNIVERSITY PKWY DEPT OF, Baltimore, MD 21218
- **Phone:** (410) 554-2284 · **Fax:** (410) 554-2184
## Medicare
- **Medicare:** Enrolled (PECOS); accepts Medicare assignment
- **Ordering & referring:** eligible for Part B labs & imaging, durable medical equipment, home health, power mobility devices
- **Bills Medicare through:** Medstar Medical Group II LLC (NPI 1184046187, Baltimore, MD), under Medicare reassignment (form CMS-855R) · CMS Revalidation Reassignment List, October 2026 release
- **Medical school:** Georgetown University School Of Medicine, class of 2015
## Record status
- **NPPES last updated:** June 11, 2025
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Source: [NPI Profile](https://npiprofile.com/npi/1043697600) · Data from the CMS NPPES public registry.