DR. MARK VINCENT WILLIAMS MD
NPI 1962425819
Hospitalist in Saint Louis, MO
About Dr. Mark Vincent Williams Md NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
DR. MARK VINCENT WILLIAMS MD (NPI 1962425819) is an individual hospitalist provider in Saint Louis, Missouri, licensed in Missouri (2021045476) and active in the NPI registry since July 2006. He is enrolled in Medicare PECOS.
NPPES Registry Identity
Specialties & Licenses 2
Other Identifiers 1
Medicare Participation & PECOS CMS
Medicare enrollment, assignment, billing reassignment, and ordering and referring status from CMS.
Medicare Enrollment Status
Enrolled in Medicare (PECOS)
Dr. Mark Vincent Williams Md is registered in the CMS Provider Enrollment, Chain and Ownership System (PECOS).
Medicare Billing Reassignment
Medicare enrollment records show Mark Williams reassigns Medicare billing to 1 organization. The organization bills Medicare for the services this provider delivers there.
Saint Louis, MO 63110
- Reassigned Medicare billing, Missouri enrollment
- 1,133 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 2
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.
Physician Visit Costs CMS claims · ZIP area
Typical Medicare office-visit costs in the 63110 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.
SAINT LOUIS, MO 63110
SAINT LOUIS, MO 63110
SAINT LOUIS, MO 63110
SAINT LOUIS, MO 63110
SAINT LOUIS, MO 63110
SAINT LOUIS, MO 63110
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 Mark Williams's NPI number?
The NPI number for Mark Williams is 1962425819. It was assigned to this individual provider in the NPPES registry on July 25, 2006.
Where is Mark Williams located?
Mark Williams practices at 1 Barnes Jewish Hospital Plz Div Im Hospitalist, Saint Louis, MO 63110. The listed phone number is (314) 362-1700.
What is Mark Williams's specialty?
The primary specialty registered for this NPI is Hospitalist with taxonomy code 208M00000X.
Is Mark Williams enrolled in Medicare?
Yes. Mark Williams is registered in the Medicare PECOS enrollment system.
Which organization bills Medicare for Mark Williams's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Mark Williams reassigns Medicare benefits to Washington University (Saint Louis, MO). 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 Mark Williams's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.
When was this NPI record last updated?
The NPPES record for Mark Williams was last updated on April 17, 2025. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 18 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. Mark Vincent Williams, MD · NPI 1962425819
Hospitalist physician in Saint Louis, Missouri. Individual provider, active in the CMS NPPES registry since July 25, 2006.
## Identity
- **NPI:** 1962425819 (Entity type: Individual)
- **Enumerated:** July 25, 2006
- **Primary specialty:** Hospitalist · taxonomy 208M00000X
- **State license:** 2021045476 (Missouri)
- **Sole proprietor:** No
## Practice location
- **Address:** 1 BARNES JEWISH HOSPITAL PLZ, DIV IM HOSPITALIST, Saint Louis, MO 63110-1003
- **Phone:** (314) 362-1700 · **Fax:** (314) 362-9878
## Medicare
- **Medicare:** Enrolled in Medicare (PECOS)
- **Ordering & referring:** eligible for Part B labs & imaging, durable medical equipment, home health, power mobility devices
- **Bills Medicare through:** Washington University (NPI 1992746903, Saint Louis, MO), under Medicare reassignment (form CMS-855R) · CMS Revalidation Reassignment List, October 2026 release
## Record status
- **NPPES last updated:** April 17, 2025
- **Other identifiers:** Medicaid 200104623 (MO)
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Source: [NPI Profile](https://npiprofile.com/npi/1962425819) · Data from the CMS NPPES public registry.