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Dermatology

Sandy H. Ro-Yim, MD

Sees patients in San Dimas, CA · City Of Industry, CA · California

Summary

Dr. Sandy H. Ro-Yim, MD is a dermatologist at 1255 W Arrow Hwy, San Dimas, CA 91773. Phone: (909) 394-2526. Accepts Medicare assignment. In 2024, Sandy H. Ro-Yim had 16 Original Medicare patients and 50 services. NPI 1821099169. Source: CMS National Downloadable File, updated October 2, 2026; CMS Medicare Physician & Other Practitioners, data year 2024.

  • Specialty: Dermatologist (Medicare lists Dermatology)
  • Address: 1255 W Arrow Hwy, San Dimas, CA 91773 · Directions (1 more location)
  • Phone: (909) 394‑2526
  • Medicare: Accepts Medicare assignment
  • Group practice: Southern California Permanente Medical Group
  • Medical school: Tufts University School Of Medicine · graduated 1993 (33 years since medical school)
  • Gender (as listed): Female

From official Medicare data

This page shows what Medicare's official clinician data says about Sandy H. Ro-Yim, joined by NPI number (data updated October 2, 2026). It is not a recommendation or a rating. Call the office or hospital to confirm before you go.

In a medical emergency, call 911.

Quick answers

Does Sandy H. Ro-Yim accept Medicare assignment?
Yes. Medicare's clinician data says Sandy H. Ro-Yim accepts Medicare assignment (the Medicare-approved amount as full payment for covered services), as of October 2, 2026. Ask the office to confirm before your visit.
How many Medicare patients does Sandy H. Ro-Yim see?
In 2024, CMS data shows 16 Original Medicare patients and 50 services for Sandy H. Ro-Yim. This counts Original Medicare only and measures volume, not quality.
What is Sandy H. Ro-Yim's NPI number?
1821099169. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.

Medicare activity in 2024

Official CMS public-use data for Sandy H. Ro-Yim, data year 2024 (released May 21, 2026). It covers Original Medicare (fee-for-service) patients only, not Medicare Advantage or other insurance. It shows volume, not quality or outcomes. CMS hides any count of 10 or fewer patients.

Original Medicare patients16
Services billed to Medicare50
Different services or procedures10
Participating Medicare providerYes
Average age of these patients67

Practice locations

Addresses where Sandy H. Ro-Yim is enrolled with Medicare (CMS data updated October 2, 2026).

Group practices

Medicare enrollment lists Sandy H. Ro-Yim as a member of this group (CMS data updated October 2, 2026).

  • Southern California Permanente Medical Group11,293 clinicians in the group

Specialties

Find other Dermatology doctors in California →

Other dermatologists in San Dimas

Clinicians with the same Medicare primary specialty in San Dimas, CA — not a recommendation.

All dermatologists in San Dimas →

Other clinicians in Southern California Permanente Medical Group

Medicare enrollment lists these clinicians in the same group practice — not a recommendation.

Clinician information

CredentialMD
Medical schoolTufts University School Of Medicine
Graduation year1993 (33 years since medical school)
Gender (as listed)Female
Medicare assignmentAccepts (Medicare-approved amount as full payment)
NPI (National Provider Identifier)1821099169
CorrectionsReport an error or suggest an update →

Most corrections must be made at the source: clinicians update their NPI Registry record (NPPES) and their Medicare enrollment (PECOS); this page follows the next data release.

Sources

  1. National Downloadable File (Doctors and Clinicians) — CMS, data updated October 2, 2026, retrieved October 29, 2026
  2. Medicare Physician & Other Practitioners - by Provider — CMS, data year 2024, released May 21, 2026; Medicare Physician & Other Practitioners - by Provider and Service
  3. NPI Registry — U.S. Department of Health and Human Services (NPPES), the clinician’s official record
  4. Medicare Care Compare — official Medicare tool to look up clinicians