Doctor profile · Federal record

Dr. Hai Nguyen, M.D.

Internal Medicine Physician (CMS: Internal Medicine) · Hospitalist Physician · General Practice Physician · Santa Ana, CA

  • NPI 1558516963
  • Accepts Medicare
  • 29 yrs in practice
  • Male
  • Group practice
  • No sanctions

Practice & contact

NPPES Updated May 11, 2026
Primary practice
2907 Sawgrass Dr
Santa Ana, CA 927061195
(714) 675-3937
fax (877) 820-4151

Credentials & registration

NPPES · NUCC
NPI registered
November 2008 — 18 yrs on file
Profile last updated
December 19, 2013
Year of graduation
1997 — 29 yrs since
Specialty taxonomy
207R00000X — NUCC code
State license (1)
California #A114137

Federal sanctions & exclusions

OIG LEIE Updated May 11, 2026

No sanctions, exclusions or revocations on file

Checked against OIG LEIE on NPI 1558516963. Last verified May 11, 2026.

Medicare procedures · 2023

Top services delivered

CMS Provider Utilization
Total services
3,278
Distinct HCPCS
5
Medicare allowed
$332,461
HCPCS Description Services Patients Avg allowed
99232 Subsequent hospital care with moderate levelof medical decision making, if using time, at least 35 minutes 2,008 140 $81
99233 Subsequent hospital care with moderate levelof medical decision making, if using time, at least 50 minutes 803 146 $121
99239 Hospital discharge day management, more than 30 minutes 198 132 $117
99223 Initial hospital care with moderate level of medical decision making, if using time, at least 75 minutes 194 125 $176
99291 Critical care, first 30-74 minutes 75 33 $216

In context: peer comparison

Among 13 peers in this city , average services per provider: 193. This provider delivers 17× the peer median.

Medicare Part D · 2023

Top prescriptions

CMS Part D Prescriber
Total claims
534
Patients
507
Total drug cost
$20,195
Drug Type Claims Patients Total cost
Prednisone Generic 59 53 $326
Cephalexin Generic 50 48 $368
Atorvastatin Calcium Generic 39 39 $258
Furosemide Generic 39 35 $159
Nitroglycerin Generic 39 39 $450
Levofloxacin Generic 38 36 $143
Metoprolol Tartrate Generic 38 37 $157
Cefdinir Generic 34 33 $487
Ondansetron Hcl Generic 34 33 $364
Clopidogrel (Clopidogrel Bisulfate) Brand 33 30 $247

Hospital affiliations

CMS Hospital Compare

Frequently asked questions

Auto-generated from federal data
What is Dr. Hai Nguyen's medical specialty?
Dr. Hai Nguyen practices Internal Medicine Physician in Santa Ana, CA.
Where does Dr. Hai Nguyen practice?
Dr. Hai Nguyen practices at 2907 Sawgrass Dr, Santa Ana, CA 927061195. Office phone: 7146753937.
What is Dr. Hai Nguyen's NPI?
Dr. Hai Nguyen's National Provider Identifier (NPI) is 1558516963, issued by NPPES.
Does Dr. Hai Nguyen accept Medicare assignment?
Yes. Dr. Hai Nguyen accepts Medicare assignment, meaning Medicare-allowed amounts are accepted as full payment for covered services.
What procedures does Dr. Hai Nguyen 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 99239). Source: CMS Medicare Physician & Other Practitioners file.