Doctor profile · Federal record

Dr. William Tsai, M.D.

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

  • NPI 1952356560
  • Accepts Medicare
  • MIPS 16.1 / 100 · 2023
  • 29 yrs in practice
  • Male
  • Solo practice
  • No sanctions

Practice & contact

NPPES Updated May 11, 2026
Primary practice
19742 Macarthur Blvd, Ste 101
Irvine, CA 926122432
(949) 955-0202
fax (949) 955-0203

Credentials & registration

NPPES · NUCC
NPI registered
May 2006 — 20 yrs on file
Profile last updated
July 16, 2010
Year of graduation
1997 — 29 yrs since
Specialty taxonomy
207R00000X — NUCC code
State license (1)
California #A71679
Medicaid
CA #00A716790

Federal sanctions & exclusions

OIG LEIE Updated May 11, 2026

No sanctions, exclusions or revocations on file

Checked against OIG LEIE on NPI 1952356560. Last verified May 11, 2026.

Medicare procedures · 2023

Top services delivered

CMS Provider Utilization
Total services
2,509
Distinct HCPCS
10
Medicare allowed
$374,724
HCPCS Description Services Patients Avg allowed
99214 Established patient office or other outpatient visit, 30-39 minutes 1,129 581 $139
99215 Established patient office or other outpatient visit, 40-54 minutes 577 419 $194
G0439 Annual wellness visit, includes a personalized prevention plan of service (pps), subsequent visit 297 297 $140
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 162 39 $58
99205 New patient office or other outpatient visit, 60-74 minutes 79 79 $237
99350 Residence visit for established patient with high level of medical decision making, per day, if using time, at least 60 minutes 73 14 $197
G0438 Annual wellness visit; includes a personalized prevention plan of service (pps), initial visit 61 61 $178
93000 Routine electrocardiogram (ecg) using at least 12 leads with interpretation and report 49 46 $16
99213 Established patient office or other outpatient visit, 20-29 minutes 37 29 $98
99349 Residence visit for established patient with moderate level of medical decision making, per day, if using time, at least 40 minutes 29 13 $135

In context: peer comparison

Among 37 peers in Irvine Internal Medicine Physician, average services per provider: 103. This provider delivers 24× the peer median.

Open Payments

Industry payments received

CMS Open Payments
All-time total
$182
Transactions
4
Manufacturers
2
Payer (manufacturer) Industry Txns Amount
Amgen INC. 1 $120.39
AstraZeneca Pharmaceuticals Lp 3 $61.92

By nature of payment

Food and Beverage
$182

Medicare Part D · 2023

Top prescriptions

CMS Part D Prescriber
Total claims
3,769
Patients
1,249
Total drug cost
$46,304
Drug Type Claims Patients Total cost
Atorvastatin Calcium Generic 756 252 $8,286
Amlodipine Besylate Generic 415 130 $3,714
Levothyroxine Sodium Generic 393 117 $5,548
Losartan Potassium Generic 330 97 $4,056
Metformin Hcl Generic 294 95 $2,221
Zolpidem Tartrate Generic 273 74 $2,552
Rosuvastatin Calcium Generic 230 77 $5,107
Alprazolam Generic 154 50 $1,391
Tamsulosin Hcl Generic 153 50 $4,060
Simvastatin Generic 144 44 $1,635

Hospital affiliations

CMS Hospital Compare

Frequently asked questions

Auto-generated from federal data
What is Dr. William Tsai's medical specialty?
Dr. William Tsai practices Internal Medicine Physician in Irvine, CA.
Where does Dr. William Tsai practice?
Dr. William Tsai practices at 19742 Macarthur Blvd, Irvine, CA 926122432. Office phone: 9499550202.
What is Dr. William Tsai's NPI?
Dr. William Tsai's National Provider Identifier (NPI) is 1952356560, 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: Established patient office or other outpatient visit (HCPCS 99214); Established patient office or other outpatient visit (HCPCS 99215); Annual wellness visit, includes a personalized prevention plan of service (pps), subsequent visit (HCPCS G0439). Source: CMS Medicare Physician & Other Practitioners file.