DR. MARCUS L WILLIAMS
NPI 1851708168
Emergency Medicine in Oakland, CA
About Dr. Marcus L Williams NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
DR. MARCUS L WILLIAMS (NPI 1851708168) is an individual emergency medicine provider in Oakland, California, licensed in California (A103108) and active in the NPI registry since July 2014. He is enrolled in Medicare PECOS and is a graduate of University Of California, Irvine, California College Of Medicine (2012).
NPPES Registry Identity
Specialties & Licenses
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. Marcus L Williams 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 Reassignments
4Medicare enrollment records show Marcus Williams reassigns Medicare billing to 4 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.
Oakland, CA 94609
- Reassigned Medicare billing, California enrollment
- 54 clinicians in this Medicare group
Alameda, CA 94501
- Reassigned Medicare billing, California enrollment
- 2,323 clinicians in this Medicare group
San Francisco, CA 94116
- Reassigned Medicare billing, California enrollment
- 20,078 clinicians in this Medicare group
Napa, CA 94558
- Reassigned Medicare billing, California enrollment
- 53 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 8
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 94602 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.
Referred Medical Equipment & Supplies CMS DME claims
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.
OAKLAND, CA 94602
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 Marcus Williams's NPI number?
The NPI number for Marcus Williams is 1851708168. It was assigned to this individual provider in the NPPES registry on July 18, 2014.
Where is Marcus Williams located?
Marcus Williams practices at 1411 E 31st St, Oakland, CA 94602. The listed phone number is (510) 437-4800.
What is Marcus Williams's specialty?
The primary specialty registered for this NPI is Emergency Medicine with taxonomy code 207P00000X.
Is Marcus Williams enrolled in Medicare?
Yes. Marcus 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 organizations bill Medicare for Marcus Williams's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Marcus Williams reassigns Medicare benefits to 4 organizations: Berkeley Emergency Medical Group, Inc. (Oakland, CA), Cep America - California (Alameda, CA), Permanente Medical Group Inc (San Francisco, CA) and Napa Valley Emergency Medical Group (Napa, CA). Each 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 Marcus 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 Marcus Williams was last updated on May 10, 2017. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 9 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. Marcus L Williams · NPI 1851708168
Emergency Medicine physician in Oakland, California. Individual provider, active in the CMS NPPES registry since July 18, 2014.
## Identity
- **NPI:** 1851708168 (Entity type: Individual)
- **Enumerated:** July 18, 2014
- **Primary specialty:** Emergency Medicine · taxonomy 207P00000X
- **State license:** A103108 (California)
- **Sole proprietor:** No
## Practice location
- **Address:** 1411 E 31ST ST, Oakland, CA 94602-1018
- **Phone:** (510) 437-4800
## 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:** 4 organizations under Medicare reassignment (form CMS-855R): Berkeley Emergency Medical Group, Inc. (NPI 1508874454, Oakland, CA); Cep America - California (NPI 1821017971, Alameda, CA); Permanente Medical Group Inc (NPI 1841373800, San Francisco, CA); Napa Valley Emergency Medical Group (NPI 1467463539, Napa, CA) · CMS Revalidation Reassignment List, October 2026 release
- **Medical school:** University Of California, Irvine, California College Of Medicine, class of 2012
## Record status
- **NPPES last updated:** May 10, 2017
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Source: [NPI Profile](https://npiprofile.com/npi/1851708168) · Data from the CMS NPPES public registry.