1. Home
  2. Directory
  3. California
  4. Fountain Valley
  5. Internal Medicine
  6. NPI Profile

DR. ROBERT S GREENFIELD MD
NPI 1649307000
Internal Medicine - Cardiovascular Disease in Fountain Valley, CA

Active since February 27, 2007PECOS Enrolled
18111 BROOKHURST ST # 5100, FOUNTAIN VALLEY, CA 92708(714) 546-2238(714) 434-8145 Get Directions Write a Review

NPPES record last updated: August 26, 2019. Verified against the NPPES registry weekly; last sync: November 01, 2026.

About Dr. Robert S Greenfield Md NPPES

Official registry information on file with the National Plan and Provider Enumeration System.

DR. ROBERT S GREENFIELD MD (NPI 1649307000) is an individual cardiovascular disease provider in Fountain Valley, California, licensed in California (G29135) and active in the NPI registry since February 2007. He is enrolled in Medicare PECOS.

NPPES Registry Identity

NPI1649307000
Entity TypeIndividualMale
Primary Taxonomy207RC0000X
Provider Legal NameDR. ROBERT S GREENFIELDCredential: MD
Location Address18111 BROOKHURST ST # 5100Fountain Valley, CA 92708-6728
Mailing Address18111 Brookhurst St # 5100Fountain Valley, CA 92708-6728 · (714) 546-2238 · Fax (714) 434-8145
Phone(714) 546-2238
Fax(714) 434-8145
Sole ProprietorYes
Enumeration DateFebruary 27, 2007
Last NPPES UpdateAugust 26, 2019
✔ NPI 1649307000 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses

★ Primary SpecialtyInternal Medicine · Cardiovascular DiseaseAllopathic & Osteopathic Physicians
Taxonomy Code207RC0000X
License✔ Licensed in CA · G29135
Definition
An internist who specializes in diseases of the heart and blood vessels and manages complex cardiac conditions such as heart attacks and life-threatening, abnormal heartbeat rhythms.
18111 BROOKHURST ST # 5100, Fountain Valley, CA 92708
Open in Google Maps ↗

Other Identifiers 1

MedicaidYYY492984YCA

Medicare Participation & PECOS CMS

Medicare enrollment, assignment, billing reassignment, and ordering and referring status from CMS.

Medicare Enrollment Status

✔

Enrolled in Medicare (PECOS)

Dr. Robert S Greenfield Md is registered in the CMS Provider Enrollment, Chain and Ownership System (PECOS).

Eligible to Order & Refer✔ Part B Labs & Imaging✔ Durable Medical Equipment✔ Home Health Agency✔ Power Mobility DevicesPer the CMS Ordering and Referring file. Eligibility means Medicare pays claims that this provider orders or refers for these categories.

Medicare Billing Reassignment

Medicare enrollment records show Robert Greenfield reassigns Medicare billing to 1 organization. The organization bills Medicare for the services this provider delivers there.

Uc Regents
7.1 mi
Allergy & Immunology
101 THE CITY DR S
Orange, CA 92868
  • Reassigned Medicare billing, California enrollment
  • 525 clinicians in this Medicare group
NPI 1003864174 (714) 456-8068

Source: CMS Revalidation Reassignment List, October 2026 release. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.

Physician Visit Costs CMS claims · ZIP area

Typical Medicare office-visit costs in the 92708 ZIP code area, from fee-for-service claims. These are area statistics, not this provider’s prices; actual charges vary by service and coverage.

New Patient
$142.39 typical visit price
range $62.96 – $187.60
Typical copayment $35.59 (range $15.74 – $46.90)
Most-billed visit code 99204
Established Patient
$77.96 typical visit price
range $20.84 – $153.61
Typical copayment $19.49 (range $5.21 – $38.40)
Most-billed visit code 99213
Amounts reflect what Medicare beneficiaries in this ZIP area are typically charged for office visits. Patients with other coverage should check their individual plans.

Other Providers at the Same Location NPPES

Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.

DR. ARVIND S NIRULA M.D.
Internal Medicine (Cardiovascular Disease)
18111 BROOKHURST ST # 5100
FOUNTAIN VALLEY, CA 92708
Orange County (714) 546-2238

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 Robert Greenfield's NPI number?

The NPI number for Robert Greenfield is 1649307000. It was assigned to this individual provider in the NPPES registry on February 27, 2007.

Where is Robert Greenfield located?

Robert Greenfield practices at 18111 Brookhurst St # 5100, Fountain Valley, CA 92708. The listed phone number is (714) 546-2238.

What is Robert Greenfield's specialty?

The primary specialty registered for this NPI is Internal Medicine, specializing in Cardiovascular Disease, with taxonomy code 207RC0000X.

Is Robert Greenfield enrolled in Medicare?

Yes. Robert Greenfield is registered in the Medicare PECOS enrollment system.

Which organization bills Medicare for Robert Greenfield's services?

According to the CMS Revalidation Reassignment List (October 2026 release), Robert Greenfield reassigns Medicare benefits to Uc Regents (Orange, CA). 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 Robert Greenfield'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 Robert Greenfield was last updated on August 26, 2019. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 7 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.