Doctor profile · Federal record

Dr. Ythanh Nguyen, MD

Internal Medicine Physician · Rancho Cucamonga, CA

  • NPI 1255391181
  • 20 yrs on file
  • Female
  • Solo practice
  • No sanctions

Practice & contact

Operates at 2 locations .

NPPES Updated May 11, 2026
Primary practice
8235 Rochester Ave
Rancho Cucamonga, CA 917300718
(909) 484-4900
fax (909) 781-2949
Additional location
999 San Bernardino RD, San Antonio Community Hospital
Upland, CA 917864920
(562) 236-3432
fax (909) 944-5904
Mailing address
154 W Foothill Blvd Ste A
Upland, CA 917868702

Credentials & registration

NPPES · NUCC
NPI registered
March 2006 — 20 yrs on file
Profile last updated
December 14, 2025
Specialty taxonomy
207R00000X — NUCC code
State license (1)
California #A84989

Federal sanctions & exclusions

OIG LEIE Updated May 11, 2026

No sanctions, exclusions or revocations on file

Checked against OIG LEIE on NPI 1255391181. Last verified May 11, 2026.

Medicare procedures · 2023

Top services delivered

CMS Provider Utilization
Total services
513
Distinct HCPCS
4
Medicare allowed
$67,958
HCPCS Description Services Patients Avg allowed
99233 Subsequent hospital care with moderate levelof medical decision making, if using time, at least 50 minutes 269 74 $121
99214 Established patient office or other outpatient visit, 30-39 minutes 92 36 $132
99223 Initial hospital care with moderate level of medical decision making, if using time, at least 75 minutes 92 76 $176
99239 Hospital discharge day management, more than 30 minutes 60 52 $117

In context: peer comparison

Among 9 peers in Rancho Cucamonga Internal Medicine Physician, average services per provider: 161. This provider delivers 3.2× the peer median.

Open Payments

Industry payments received

CMS Open Payments
All-time total
$121
Transactions
5
Manufacturers
3
Payer (manufacturer) Industry Txns Amount
Pfizer INC. 3 $66.20
Janssen Pharmaceuticals, INC 1 $27.79
Insmed, INC. 1 $27.42

By nature of payment

Food and Beverage
$121

Medicare Part D · 2023

Top prescriptions

CMS Part D Prescriber
Total claims
803
Patients
476
Total drug cost
$99,708
Drug Type Claims Patients Total cost
Furosemide Generic 107 66 $893
Carvedilol Generic 83 43 $997
Eliquis (Apixaban) Brand 71 33 $56,146
Levofloxacin Generic 66 63 $299
Prednisone Generic 59 45 $408
Amlodipine Besylate Generic 58 40 $488
Hydrocodone-Acetaminophen (Hydrocodone/Acetaminophen) Brand 56 40 $666
Atorvastatin Calcium Generic 49 22 $1,173
Pantoprazole Sodium Generic 43 29 $647
Losartan Potassium Generic 42 18 $616

Frequently asked questions

Auto-generated from federal data
What is Dr. Ythanh Nguyen's medical specialty?
Dr. Ythanh Nguyen practices Internal Medicine Physician in Rancho Cucamonga, CA.
Where does Dr. Ythanh Nguyen practice?
Dr. Ythanh Nguyen practices at 8235 Rochester Ave, Rancho Cucamonga, CA 917300718. Office phone: 9094844900.
What is Dr. Ythanh Nguyen's NPI?
Dr. Ythanh Nguyen's National Provider Identifier (NPI) is 1255391181, issued by NPPES.
What procedures does Dr. Ythanh Nguyen commonly perform?
Top Medicare-reported procedures in 2023: Subsequent hospital care with moderate levelof medical decision making (HCPCS 99233); Established patient office or other outpatient visit (HCPCS 99214); Initial hospital care with moderate level of medical decision making (HCPCS 99223). Source: CMS Medicare Physician & Other Practitioners file.