DEREK D MAFONG M.D.
NPI 1699781633
Internal Medicine - Endocrinology, Diabetes & Metabolism in San Diego, CA
About Derek D Mafong M.d. NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
DEREK D MAFONG M.D. (NPI 1699781633) is an individual endocrinology, diabetes & metabolism provider in San Diego, California, licensed in California (A89536) and active in the NPI registry since July 2006. He is enrolled in Medicare PECOS and is a graduate of University Of California, San Francisco School Of Medicine (2001).
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
Derek D Mafong M.d. 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
2Medicare enrollment records show Derek Mafong reassigns Medicare billing to 2 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.
San Diego, CA 92103
- Reassigned Medicare billing, California enrollment
- Medicare enrollment name: Regents Of The University Of California
- 1,051 clinicians in this Medicare group
San Diego, CA 92108
- Reassigned Medicare billing, California enrollment
- 13,921 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.
Physician Visit Costs CMS claims · ZIP area
Typical Medicare office-visit costs in the 92103 ZIP code area, from fee-for-service claims. These are area statistics, not this provider’s prices; actual charges vary by service and coverage.
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.
SAN DIEGO, CA 92103
SAN DIEGO, CA 92103
SAN DIEGO, CA 92103
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 Derek Mafong's NPI number?
The NPI number for Derek Mafong is 1699781633. It was assigned to this individual provider in the NPPES registry on July 31, 2006.
Where is Derek Mafong located?
Derek Mafong practices at 200 W Arbor Dr, San Diego, CA 92103. The listed phone number is (800) 926-8273.
What is Derek Mafong's specialty?
The primary specialty registered for this NPI is Internal Medicine, specializing in Endocrinology, Diabetes & Metabolism, with taxonomy code 207RE0101X.
Is Derek Mafong enrolled in Medicare?
Yes. Derek Mafong 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 Derek Mafong's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Derek Mafong reassigns Medicare benefits to 2 organizations: Regents Of The University Of California - Ucsd Medical Group (San Diego, CA) and Southern California Permanente Medical Group (San Diego, 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 Derek Mafong'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 Derek Mafong was last updated on December 2, 2021. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 4 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.
# Derek D Mafong, M.D. · NPI 1699781633
Endocrinology, Diabetes & Metabolism physician in San Diego, California. Individual provider, active in the CMS NPPES registry since July 31, 2006.
## Identity
- **NPI:** 1699781633 (Entity type: Individual)
- **Enumerated:** July 31, 2006
- **Primary specialty:** Internal Medicine - Endocrinology, Diabetes & Metabolism · taxonomy 207RE0101X
- **State license:** A89536 (California)
- **Sole proprietor:** Yes
## Practice location
- **Address:** 200 W ARBOR DR, San Diego, CA 92103-9000
- **Phone:** (800) 926-8273
## 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:** 2 organizations under Medicare reassignment (form CMS-855R): Regents Of The University Of California - Ucsd Medical Group (NPI 1336267137, San Diego, CA); Southern California Permanente Medical Group (NPI 1023425972, San Diego, CA) · CMS Revalidation Reassignment List, October 2026 release
- **Medical school:** University Of California, San Francisco School Of Medicine, class of 2001
## Record status
- **NPPES last updated:** December 2, 2021
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Source: [NPI Profile](https://npiprofile.com/npi/1699781633) · Data from the CMS NPPES public registry.