Doctor profile · Federal record

Dr. William Tsai, D.O.

Family Medicine Physician (CMS: Family Practice) · Upland, CA

  • NPI 1285620443
  • Accepts Medicare
  • 30 yrs in practice
  • Male
  • Group practice
  • No sanctions

Practice & contact

NPPES Updated May 11, 2026
Primary practice
510 N 13Th Ave Ste 101
Upland, CA 917864973
(909) 985-8838
fax (909) 985-8899

Credentials & registration

NPPES · NUCC
NPI registered
September 2005 — 21 yrs on file
Profile last updated
April 24, 2024
Year of graduation
1996 — 30 yrs since
Specialty taxonomy
207Q00000X — NUCC code
State license (1)
California #20A7115
Medicaid
CA #00AX71150

Federal sanctions & exclusions

OIG LEIE Updated May 11, 2026

No sanctions, exclusions or revocations on file

Checked against OIG LEIE on NPI 1285620443. Last verified May 11, 2026.

Medicare procedures · 2023

Top services delivered

CMS Provider Utilization
Total services
804
Distinct HCPCS
8
Medicare allowed
$65,834
HCPCS Description Services Patients Avg allowed
99497 Advance care planning, first 30 minutes 223 24 $77
99213 Established patient office or other outpatient visit, 20-29 minutes 171 71 $91
99308 Subsequent nursing facility care with straightforward level of medical decision making, per day, if using time, at least 15 minutes 165 22 $77
99348 Residence visit for established patient with low level of medical decision making, per day, if using time, at least 30 minutes 129 13 $79
99442 Telephone medical discussion with physician, 11-20 minutes 52 25 $92
G0179 Physician or allowed practitioner re-certification for medicare-covered home health services under a home health plan of care (patient not present), including contacts with home health agency and review of reports of patient status required by physicians a 26 12 $43
99306 Initial nursing facility care with high level of medical decision making, per day, if using time, at least 45 minutes 22 13 $148
G0180 Physician or allowed practitioner certification for medicare-covered home health services under a home health plan of care (patient not present), including contacts with home health agency and review of reports of patient status required by physicians and 16 12 $54

In context: peer comparison

Among 8 peers in Upland Family Medicine Physician, average services per provider: 109. This provider delivers 7.4× the peer median.

Open Payments

Industry payments received

CMS Open Payments
All-time total
$1,291
Transactions
45
Manufacturers
15
Payer (manufacturer) Industry Txns Amount
Novartis Pharmaceuticals Corporation 10 $180.36
Inari Medical, INC. 1 $176.73
Lilly USA, LLC 8 $173.80
Teva Pharmaceuticals USA, INC. 3 $99.84
Novo Nordisk INC 4 $87.07
Pfizer INC. 3 $73.93
Otsuka America Pharmaceutical, INC. 3 $69.93
AstraZeneca Pharmaceuticals Lp 3 $60.24
Exact Sciences Corporation 2 $44.60
Boehringer Ingelheim Pharmaceuticals, INC. 2 $42.37
Sumitomo Pharma America, INC. 2 $39.23
Hologic Sales and Service, LLC 1 $27.26
Bayer Healthcare Pharmaceuticals INC. 1 $26.50
Insmed, INC. 1 $24.92
Shield Therapeutics INC 1 $24.68

By nature of payment

Food and Beverage
$1,291

Medicare Part D · 2023

Top prescriptions

CMS Part D Prescriber
Total claims
4,465
Patients
1,018
Total drug cost
$67,911
Drug Type Claims Patients Total cost
Atorvastatin Calcium Generic 970 228 $15,629
Amlodipine Besylate Generic 581 143 $5,197
Levothyroxine Sodium Generic 471 73 $6,535
Losartan Potassium Generic 365 93 $5,383
Metformin Hcl Generic 295 76 $2,757
Carvedilol Generic 231 46 $2,255
Tamsulosin Hcl Generic 226 58 $3,630
Trazodone Hcl Generic 200 40 $2,180
Furosemide Generic 172 35 $1,065
Hydrocodone-Acetaminophen (Hydrocodone/Acetaminophen) Brand 170 40 $3,933

Frequently asked questions

Auto-generated from federal data
What is Dr. William Tsai's medical specialty?
Dr. William Tsai practices Family Medicine Physician in Upland, CA.
Where does Dr. William Tsai practice?
Dr. William Tsai practices at 510 N 13Th Ave Ste 101, Upland, CA 917864973. Office phone: 9099858838.
What is Dr. William Tsai's NPI?
Dr. William Tsai's National Provider Identifier (NPI) is 1285620443, issued by NPPES.
Does Dr. William Tsai accept Medicare assignment?
Yes. Dr. William Tsai accepts Medicare assignment, meaning Medicare-allowed amounts are accepted as full payment for covered services.
What procedures does Dr. William Tsai commonly perform?
Top Medicare-reported procedures in 2023: Advance care planning (HCPCS 99497); Established patient office or other outpatient visit (HCPCS 99213); Subsequent nursing facility care with straightforward level of medical decision making (HCPCS 99308). Source: CMS Medicare Physician & Other Practitioners file.