Elmer Chang, M.D.
NPI 1912083353 · Gastroenterology Physician · Mission Viejo, CA
Enrolled with Medicare as Practitioner - Gastroenterology · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Elmer Chang, M.D. is a Gastroenterology Physician provider in Mission Viejo, CA (NPI 1912083353).
Provider details
- NPI number
- 1912083353
- Entity type
- Individual
- Primary specialty
- Gastroenterology PhysicianAllopathic & Osteopathic Physicians
- Credential
- M.D.
- Sex
- Male
- Sole proprietor
- No
- License
- A75579 (CA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure25% of score
19 yrs in NPPES registry
- Profile completeness25% of score
100% of core fields populated
- Practice footprint15% of score
1 documented practice location
- Medicare service volume (vs. specialty peers)25% of score
1,259 Medicare services, 2024 (ranked within specialty)
- Open Payments transparency10% of score
Has Open Payments disclosures (2024)
Medicare volume is ranked against active providers in the same specialty. Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our .
What this provider does (Medicare)
Based on Medicare fee-for-service claims, 2024; not all care is captured.
| Service (HCPCS) | Medicare services | Typical Medicare-allowed (2024) |
|---|---|---|
| Established Patient Office Or Other Outpatient Visit With Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 328 | $136 |
| Biopsy of Large Bowel Using a Flexible Endoscope45380 | 192 | $73 |
| Biopsy of Esophagus, Stomach, And/Or Upper Small Bowel Using a Flexible Endoscope43239 | 149 | $45 |
| Established Patient Office Or Other Outpatient Visit With Low Level OD Decision Making, If Using Time, 20 Minutes Or More99213 | 149 | $98 |
| Removal of Polyps Or Growths of Large Bowel Using an Endoscope With Mechanical Snare45385 | 130 | $232 |
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 22 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Omeprazole | 719 | 252 |
| Famotidine | 534 | 210 |
| Pantoprazole Sodium | 197 | 70 |
| Sodium, Potassium,mag Sulfatesbrand: Sod Sulf-Potass Sulf-Mag Sulf | 184 | 175 |
| Sucralfate | 99 | 62 |
| Peg3350/Sod Sulf,bicarb,cl/Kclbrand: Gavilyte-C | 68 | 64 |
| Hydrocortisone | 60 | 38 |
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$4,328 across 173 records (Open Payments 2024)
Open Payments discloses payments and transfers of value (meals, travel, consulting, research, royalties) from drug and device makers to providers. This is a transparency signal, not a verdict — such payments are legal and common, and their presence is neither an endorsement nor a criticism. Source: CMS Open Payments, program year 2024.
Practice location
Mailing address
Registry dates
- Enumerated
- 2006-10-28
- Last updated
- 2013-01-23
Frequently asked questions
- What is Elmer Chang's NPI number?
- Elmer Chang's National Provider Identifier (NPI) is 1912083353, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Elmer Chang's specialty?
- Elmer Chang is listed in the NPPES registry with a primary specialty of Gastroenterology Physician (Allopathic & Osteopathic Physicians).
- Where is Elmer Chang located?
- Elmer Chang's practice location on file with NPPES is 27871 Medical Center Rd, Mission Viejo, CA 92691-6404.
- What is Elmer Chang's phone number?
- The practice phone number listed in the NPPES registry for Elmer Chang is (949) 364-5090.
- Does Elmer Chang accept Medicare?
- Elmer Chang is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Elmer Chang's NPI active?
- Yes — Elmer Chang's NPI (1912083353) is active in the NPPES registry as of the last update on 2013-01-23.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.