DR. CALVIN THOMAS WILLIAMS JR. M.D. / PH.D
NPI 1023308640
Internal Medicine - Infectious Disease in Baltimore, MD
About Dr. Calvin Thomas Williams Jr. M.d. / Ph.d NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
DR. CALVIN THOMAS WILLIAMS JR. M.D. / PH.D (NPI 1023308640) is an individual infectious disease provider in Baltimore, Maryland, licensed in Maryland (D0081038) and active in the NPI registry since April 2011. He is enrolled in Medicare PECOS, is affiliated with Medstar Franklin Square Medical Center, and is a graduate of University Of Maryland School Of Medicine (2011).
NPPES Registry Identity
Specialties & Licenses 3
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. Calvin Thomas Williams Jr. M.d. / Ph.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 Calvin Williams reassigns Medicare billing to 1 organization. The organization bills Medicare for the services this provider delivers there.
Baltimore, MD 21239
- Reassigned Medicare billing, Maryland enrollment
- 2,602 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.
Areas of Expertise CMS Part B claims 3
Services this provider delivered to Medicare fee-for-service patients, from the CMS Medicare utilization data. Higher counts generally reflect more experience with a service; care delivered outside Medicare is not included.
Hospital Affiliations CMS Care Compare 3
Hospitals where this provider delivers care, identified from recent Medicare claims and place-of-service records.
Medstar Franklin Square Medical Center
Acute Care Hospitals · Rosedale, MDMedstar Union Memorial Hospital
Acute Care Hospitals · Baltimore, MDMedstar Good Samaritan Hospital
Acute Care Hospitals · Baltimore, MDPhysician Visit Costs CMS claims · ZIP area
Typical Medicare office-visit costs in the 21218 ZIP code area, from fee-for-service claims. These are area statistics, not this provider’s prices; actual charges vary by service and coverage.
Medicare Quality Performance CMS QPP · MIPS
Performance in the CMS Quality Payment Program: the MIPS final score across four weighted categories, and the individual quality measures reported to Medicare.
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 Calvin Williams's NPI number?
The NPI number for Calvin Williams is 1023308640. It was assigned to this individual provider in the NPPES registry on April 15, 2011.
Where is Calvin Williams located?
Calvin Williams practices at 201 E University Pkwy Dept Of Medicine Medstar Union Memorial Hospital, Baltimore, MD 21218. The listed phone number is (443) 474-9911.
What is Calvin Williams's specialty?
The primary specialty registered for this NPI is Internal Medicine, specializing in Infectious Disease, with taxonomy code 207RI0200X.
Is Calvin Williams enrolled in Medicare?
Yes. Calvin Williams 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 Calvin Williams's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Calvin Williams 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 Calvin Williams's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.
Is Calvin Williams affiliated with any hospitals?
According to CMS data, Calvin Williams is affiliated with Medstar Franklin Square Medical Center, Medstar Union Memorial Hospital and Medstar Good Samaritan Hospital.
When was this NPI record last updated?
The NPPES record for Calvin Williams was last updated on April 24, 2018. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 8 years 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. Calvin Thomas Williams Jr., M.D. / PH.D · NPI 1023308640
Infectious Disease physician in Baltimore, Maryland. Individual provider, active in the CMS NPPES registry since April 15, 2011.
## Identity
- **NPI:** 1023308640 (Entity type: Individual)
- **Enumerated:** April 15, 2011
- **Primary specialty:** Internal Medicine - Infectious Disease · taxonomy 207RI0200X
- **State license:** D0081038 (Maryland)
- **Sole proprietor:** No
## Practice location
- **Address:** 201 E UNIVERSITY PKWY, DEPT OF MEDICINE MEDSTAR UNION MEMORIAL HOSPITAL, Baltimore, MD 21218-2829
- **Phone:** (443) 474-9911
## 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:** University Of Maryland School Of Medicine, class of 2011
## Record status
- **NPPES last updated:** April 24, 2018
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Source: [NPI Profile](https://npiprofile.com/npi/1023308640) · Data from the CMS NPPES public registry.