DR. BENJAMIN LOUIS MAZER M.D.
NPI 1689022352
Pathology - Anatomic Pathology & Clinical Pathology in Baltimore, MD
About Dr. Benjamin Louis Mazer M.d. NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
DR. BENJAMIN LOUIS MAZER M.D. (NPI 1689022352) is an individual anatomic pathology & clinical pathology provider in Baltimore, Maryland, licensed in Maryland (D88601) and active in the NPI registry since June 2016. He is enrolled in Medicare PECOS, is affiliated with Johns Hopkins Bayview Medical Center, and is a graduate of University Of Rochester School Of Medicine And Dentistry (2016).
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 (PECOS)
Dr. Benjamin Louis Mazer M.d. is registered in the CMS Provider Enrollment, Chain and Ownership System (PECOS).
Medicare Billing Reassignments
2Medicare enrollment records show Benjamin Mazer reassigns Medicare billing to 2 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.
Baltimore, MD 21205
- Reassigned Medicare billing, Maryland enrollment
- 4,483 clinicians in this Medicare group
Baltimore, MD 21287
- Reassigned Medicare billing, District of Columbia enrollment
- 62 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 15
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
Hospitals where this provider delivers care, identified from recent Medicare claims and place-of-service records.
Johns Hopkins Bayview Medical Center
Acute Care Hospitals · Baltimore, MDPhysician Visit Costs CMS claims · ZIP area
Typical Medicare office-visit costs in the 21287 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 21287
BALTIMORE, MD 21287
BALTIMORE, MD 21287
BALTIMORE, MD 21287
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 Benjamin Mazer's NPI number?
The NPI number for Benjamin Mazer is 1689022352. It was assigned to this individual provider in the NPPES registry on June 2, 2016.
Where is Benjamin Mazer located?
Benjamin Mazer practices at 600 N Wolfe St, Baltimore, MD 21287. The listed phone number is (410) 955-3580.
What is Benjamin Mazer's specialty?
The primary specialty registered for this NPI is Pathology, specializing in Anatomic Pathology & Clinical Pathology, with taxonomy code 207ZP0102X.
Is Benjamin Mazer enrolled in Medicare?
Yes. Benjamin Mazer is registered in the Medicare PECOS enrollment system.
Which organizations bill Medicare for Benjamin Mazer's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Benjamin Mazer reassigns Medicare benefits to 2 organizations: Johns Hopkins University (Baltimore, MD) and Johns Hopkins University (Baltimore, MD). 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 Benjamin Mazer's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.
Is Benjamin Mazer affiliated with any hospitals?
According to CMS data, Benjamin Mazer is affiliated with Johns Hopkins Bayview Medical Center.
When was this NPI record last updated?
The NPPES record for Benjamin Mazer was last updated on April 14, 2021. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 5 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. Benjamin Louis Mazer, M.D. · NPI 1689022352
Anatomic Pathology & Clinical Pathology physician in Baltimore, Maryland. Individual provider, active in the CMS NPPES registry since June 2, 2016.
## Identity
- **NPI:** 1689022352 (Entity type: Individual)
- **Enumerated:** June 2, 2016
- **Primary specialty:** Pathology - Anatomic Pathology & Clinical Pathology · taxonomy 207ZP0102X
- **State license:** D88601 (Maryland)
- **Sole proprietor:** No
## Practice location
- **Address:** 600 N WOLFE ST, Baltimore, MD 21287-0005
- **Phone:** (410) 955-3580 · **Fax:** (410) 550-0075
## 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:** 2 organizations under Medicare reassignment (form CMS-855R): Johns Hopkins University (NPI 1033190442, Baltimore, MD); Johns Hopkins University (NPI 1477540904, Baltimore, MD) · CMS Revalidation Reassignment List, October 2026 release
- **Medical school:** University Of Rochester School Of Medicine And Dentistry, class of 2016
## Record status
- **NPPES last updated:** April 14, 2021
---
Source: [NPI Profile](https://npiprofile.com/npi/1689022352) · Data from the CMS NPPES public registry.