MS. KEIKO IWAHARA GREENBERG
NPI 1588807408
Internal Medicine - Nephrology in Baltimore, MD
About Ms. Keiko Iwahara Greenberg NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
MS. KEIKO IWAHARA GREENBERG (NPI 1588807408) is an individual nephrology provider in Baltimore, Maryland, licensed in Maryland (D0079185) and active in the NPI registry since April 2009. She is enrolled in Medicare PECOS and is a graduate of University Of Virginia School Of Medicine (2009).
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
Ms. Keiko Iwahara Greenberg 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
3Medicare enrollment records show Keiko Greenberg reassigns Medicare billing to 3 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.
Baltimore, MD 21287
- Reassigned Medicare billing, Maryland enrollment
- 4,483 clinicians in this Medicare group
Baltimore, MD 21239
- Reassigned Medicare billing, District of Columbia enrollment
- 3,530 clinicians in this Medicare group
Washington, DC 20007
- Reassigned Medicare billing, District of Columbia enrollment
- 861 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 13
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 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.
Referred 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 13
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
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 Keiko Greenberg's NPI number?
The NPI number for Keiko Greenberg is 1588807408. It was assigned to this individual provider in the NPPES registry on April 7, 2009.
Where is Keiko Greenberg located?
Keiko Greenberg practices at 1830 E Monument St Ste 416, Baltimore, MD 21287. The listed phone number is (410) 955-5268.
What is Keiko Greenberg's specialty?
The primary specialty registered for this NPI is Internal Medicine, specializing in Nephrology, with taxonomy code 207RN0300X.
Is Keiko Greenberg enrolled in Medicare?
Yes. Keiko Greenberg 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 Keiko Greenberg's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Keiko Greenberg reassigns Medicare benefits to 3 organizations: Johns Hopkins University (Baltimore, MD), Medstar Medical Group II LLC (Baltimore, MD) and Mgmc LLC (Washington, DC). 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 Keiko Greenberg'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 Keiko Greenberg was last updated on January 1, 2016. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 10 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.
# Ms. Keiko Iwahara Greenberg · NPI 1588807408
Nephrology physician in Baltimore, Maryland. Individual provider, active in the CMS NPPES registry since April 7, 2009.
## Identity
- **NPI:** 1588807408 (Entity type: Individual)
- **Enumerated:** April 7, 2009
- **Primary specialty:** Internal Medicine - Nephrology · taxonomy 207RN0300X
- **State license:** D0079185 (Maryland)
- **Sole proprietor:** No
## Practice location
- **Address:** 1830 E MONUMENT ST STE 416, Baltimore, MD 21287-0020
- **Phone:** (410) 955-5268
## 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:** 3 organizations under Medicare reassignment (form CMS-855R): Johns Hopkins University (NPI 1023018413, Baltimore, MD); Medstar Medical Group II LLC (NPI 1184046187, Baltimore, MD); Mgmc LLC (NPI 1316949654, Washington, DC) · CMS Revalidation Reassignment List, October 2026 release
- **Medical school:** University Of Virginia School Of Medicine, class of 2009
## Record status
- **NPPES last updated:** January 1, 2016
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Source: [NPI Profile](https://npiprofile.com/npi/1588807408) · Data from the CMS NPPES public registry.