Doctor profile · Federal record

Dr. Stephen Yoon, M.D.

Internal Medicine Physician (CMS: Internal Medicine) · Fullerton, CA

  • NPI 1851327100
  • Accepts Medicare
  • 28 yrs in practice
  • Male
  • Group practice
  • No sanctions

Practice & contact

NPPES Updated May 11, 2026
Primary practice
101 E Valencia Mesa Dr
Fullerton, CA 928353809
(714) 992-3000

Credentials & registration

NPPES · NUCC
NPI registered
June 2006 — 20 yrs on file
Profile last updated
May 13, 2015
Year of graduation
1998 — 28 yrs since
Specialty taxonomy
207R00000X — NUCC code
State license (1)
California #A71645

Federal sanctions & exclusions

OIG LEIE Updated May 11, 2026

No sanctions, exclusions or revocations on file

Checked against OIG LEIE on NPI 1851327100. Last verified May 11, 2026.

Medicare procedures · 2023

Top services delivered

CMS Provider Utilization
Total services
810
Distinct HCPCS
6
Medicare allowed
$86,529
HCPCS Description Services Patients Avg allowed
99232 Subsequent hospital care with moderate levelof medical decision making, if using time, at least 35 minutes 303 166 $83
99233 Subsequent hospital care with moderate levelof medical decision making, if using time, at least 50 minutes 294 135 $125
99238 Hospital discharge day management, 30 minutes or less 85 85 $86
99239 Hospital discharge day management, more than 30 minutes 64 63 $121
99222 Initial hospital care with straightforward or low-level medical decision making, if using time, at least 55 minutes 46 46 $137
99223 Initial hospital care with moderate level of medical decision making, if using time, at least 75 minutes 18 18 $182

In context: peer comparison

Among 14 peers in this city , average services per provider: 146. This provider delivers 5.5× the peer median.

Open Payments

Industry payments received

CMS Open Payments
All-time total
$145
Transactions
6
Manufacturers
3
Payer (manufacturer) Industry Txns Amount
PFIZER INC. 4 $89.04
ZOLL Services LLC (A/K/A ZOLL LifeCor Corp) 1 $36.18
Janssen Pharmaceuticals, Inc 1 $19.37

By nature of payment

Food and Beverage
$145

Medicare Part D · 2023

Top prescriptions

CMS Part D Prescriber
Total claims
261
Patients
203
Total drug cost
$23,059
Drug Type Claims Patients Total cost
Amoxicillin-Clavulanate Potass (Amoxicillin/Potassium Clav) Brand 67 66 $487
Eliquis (Apixaban) Brand 33 20 $21,616
Pantoprazole Sodium Generic 30 21 $173
Furosemide Generic 22 18 $63
Atorvastatin Calcium Generic 20 13 $204
Prednisone Generic 19 17 $159
Metoprolol Tartrate Generic 18 13 $64
Carvedilol Generic 15 12 $83
Clopidogrel (Clopidogrel Bisulfate) Brand 14 0 $68
Ciprofloxacin Hcl Generic 12 12 $91

Frequently asked questions

Auto-generated from federal data
What is Dr. Stephen Yoon's medical specialty?
Dr. Stephen Yoon practices Internal Medicine Physician in Fullerton, CA.
Where does Dr. Stephen Yoon practice?
Dr. Stephen Yoon practices at 101 E Valencia Mesa Dr, Fullerton, CA 928353809. Office phone: 7149923000.
What is Dr. Stephen Yoon's NPI?
Dr. Stephen Yoon's National Provider Identifier (NPI) is 1851327100, issued by NPPES.
Does Dr. Stephen Yoon accept Medicare assignment?
Yes. Dr. Stephen Yoon accepts Medicare assignment, meaning Medicare-allowed amounts are accepted as full payment for covered services.
What procedures does Dr. Stephen Yoon commonly perform?
Top Medicare-reported procedures in 2023: Subsequent hospital care with moderate levelof medical decision making (HCPCS 99232); Subsequent hospital care with moderate levelof medical decision making (HCPCS 99233); Hospital discharge day management (HCPCS 99238). Source: CMS Medicare Physician & Other Practitioners file.