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Emergency Medicine

Christepher D. Yao, MD

Works at hospitals in Orange, CA · California

Summary

Dr. Christepher D. Yao, MD is an emergency medicine doctor at 1100 W Stewart Dr, Orange, CA 92868. Phone: (714) 633-9111. Accepts Medicare assignment. In 2024, Christepher D. Yao had 341 Original Medicare patients and 516 services. NPI 1649237637. Source: CMS National Downloadable File, updated October 2, 2026; CMS Facility Affiliation Data, updated October 2, 2026; CMS Medicare Physician & Other Practitioners, data year 2024.

  • Specialty: Emergency medicine doctor (Medicare lists Emergency Medicine)
  • Address: 1100 W Stewart Dr, Orange, CA 92868 · Directions
  • Phone: (714) 633‑9111
  • Medicare: Accepts Medicare assignment
  • Hospital: Providence St. Joseph Hospital
  • Group practice: Emergency Medicine Specialists of Orange County
  • Medical school: graduated 2004 (22 years since medical school)
  • Gender (as listed): Male

From official Medicare data

This page shows what Medicare's official clinician data says about Christepher D. Yao, 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 Christepher D. Yao accept Medicare assignment?
Yes. Medicare's clinician data says Christepher D. Yao 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 Christepher D. Yao see?
In 2024, CMS data shows 341 Original Medicare patients and 516 services for Christepher D. Yao. This counts Original Medicare only and measures volume, not quality.
What is Christepher D. Yao's NPI number?
1649237637. 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 Christepher D. Yao, 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 patients341
Services billed to Medicare516
Different services or procedures24
Participating Medicare providerYes
Average age of these patients75

Most frequent services

  1. Emergency department visit with high level of medical decision making (99285)151 services
  2. Routine electrocardiogram (ecg) using at least 12 leads with interpretation and report only (93010)141 services
  3. Critical care, first 30-74 minutes (99291)121 services
  4. Emergency department visit with moderate level of medical decision making (99284)53 services
  5. Initial hospital care with moderate level of medical decision making, if using time, at least 75 minutes (99223)15 services

Chronic conditions among these patients

Share of this clinician’s Original Medicare patients with each condition, as published by CMS (it describes the patients, not the care given).

  • High blood pressure75%
  • High cholesterol75%
  • Arthritis54%
  • Diabetes46%
  • Ischemic heart disease44%
  • Chronic kidney disease42%

Hospitals where Christepher D. Yao works

Medicare's Facility Affiliation Data lists Christepher D. Yao at these hospitals (updated October 2, 2026). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians. Star rating and emergency services: Hospital General Information (CMS), data updated October 26, 2026.

Practice locations

Addresses where Christepher D. Yao is enrolled with Medicare (CMS data updated October 2, 2026).

Group practices

Medicare enrollment lists Christepher D. Yao as a member of this group (CMS data updated October 2, 2026).

  • Emergency Medicine Specialists of Orange County42 clinicians in the group

Specialties

Find other Emergency Medicine doctors in California →

Other emergency medicine doctors in Orange

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

All emergency medicine doctors in Orange →

Other clinicians in Emergency Medicine Specialists of Orange County

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

Clinician information

CredentialMD
Graduation year2004 (22 years since medical school)
Gender (as listed)Male
Medicare assignmentAccepts (Medicare-approved amount as full payment)
NPI (National Provider Identifier)1649237637
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. Facility Affiliation Data — Centers for Medicare & Medicaid Services (CMS), data updated October 2, 2026, retrieved October 29, 2026
  2. Hospital General Information — CMS, data updated October 26, 2026, retrieved November 13, 2026
  3. National Downloadable File (Doctors and Clinicians) — CMS, data updated October 2, 2026, retrieved October 29, 2026
  4. Medicare Physician & Other Practitioners - by Provider — CMS, data year 2024, released May 21, 2026; Medicare Physician & Other Practitioners - by Provider and Service
  5. NPI Registry — U.S. Department of Health and Human Services (NPPES), the clinician’s official record
  6. Medicare Care Compare — official Medicare tool to look up clinicians