Doctor profile · Federal record

Dr. Timothy Byun, MD

Hematology & Oncology Physician (CMS: Hematology/Oncology) · Orange, CA

  • NPI 1871545012
  • Accepts Medicare
  • 28 yrs in practice
  • Male
  • Group practice
  • No sanctions

Practice & contact

Operates at 2 locations .

NPPES Updated May 11, 2026
Primary practice
805 W la Veta Ave Ste 101
Orange, CA 928683928
(714) 835-1800
Additional location
1010 W la Veta Ave, #200
Orange, CA 928684300
fax (714) 835-1811

Credentials & registration

NPPES · NUCC
NPI registered
May 2006 — 20 yrs on file
Profile last updated
June 4, 2024
Year of graduation
1998 — 28 yrs since
Specialty taxonomy
207RH0003X — NUCC code
State license (1)
California #A70195
Medicaid
CA #00A701950734

Federal sanctions & exclusions

OIG LEIE Updated May 11, 2026

No sanctions, exclusions or revocations on file

Checked against OIG LEIE on NPI 1871545012. Last verified May 11, 2026.

Medicare procedures · 2023

Top services delivered

CMS Provider Utilization
Total services
1,593
Distinct HCPCS
10
Medicare allowed
$137,514
HCPCS Description Services Patients Avg allowed
99214 Established patient office or other outpatient visit, 30-39 minutes 546 280 $139
85025 Complete blood cell count (red cells, white blood cell, platelets), automated test and automated differential white blood cell count 261 91 $8
36415 Insertion of needle into vein for collection of blood sample 257 96 $8
99233 Subsequent hospital care with moderate levelof medical decision making, if using time, at least 50 minutes 101 23 $125
80053 Blood test, comprehensive group of blood chemicals 74 34 $10
96413 Administration of chemotherapy into vein, 1 hour or less 69 23 $152
99205 New patient office or other outpatient visit, 60-74 minutes 65 65 $237
99213 Established patient office or other outpatient visit, 20-29 minutes 51 40 $98
99442 Telephone medical discussion with physician, 11-20 minutes 51 46 $92
96372 Injection of drug or substance under skin or into muscle 39 16 $16

In context: peer comparison

Among 20 peers in this city , average services per provider: 1,067. This provider delivers 1.5× the peer median.

Open Payments

Industry payments received

CMS Open Payments
All-time total
$6,726
Transactions
174
Manufacturers
15
Payer (manufacturer) Industry Txns Amount
AstraZeneca Pharmaceuticals LP 17 $2,072.05
PFIZER INC. 28 $536.60
Novartis Pharmaceuticals Corporation 21 $486.19
Merck Sharp & Dohme LLC 10 $231.31
Exelixis Inc. 7 $212.25
GlaxoSmithKline, LLC. 13 $203.33
E.R. Squibb & Sons, L.L.C. 18 $198.46
ABBVIE INC. 14 $190.75
Sumitomo Pharma America, Inc. 8 $162.04
Janssen Biotech, Inc. 8 $156.38
ARRAY BIOPHARMA INC 8 $152.58
Genentech USA, Inc. 5 $145.14
Daiichi Sankyo Inc. 5 $143.36
Astellas Pharma US Inc 6 $139.76
Gilead Sciences, Inc. 6 $136.69

By nature of payment

Food and Beverage
$5,061
Consulting Fee
$1,665

Medicare Part D · 2023

Top prescriptions

CMS Part D Prescriber
Total claims
755
Patients
173
Total drug cost
$2,001,977
Drug Type Claims Patients Total cost
Anastrozole Generic 129 43 $4,204
Xtandi (Enzalutamide) Brand 86 12 $1,242,713
Acyclovir Generic 66 17 $1,447
Prednisone Generic 61 15 $313
Levothyroxine Sodium Generic 59 15 $1,102
Eliquis (Apixaban) Brand 55 18 $66,764
Dexamethasone Generic 40 15 $409
Imatinib Mesylate Generic 38 0 $108,576
Letrozole Generic 37 0 $1,673
Orgovyx (Relugolix) Brand 34 0 $89,898

Hospital affiliations

CMS Hospital Compare

Frequently asked questions

Auto-generated from federal data
What is Dr. Timothy Byun's medical specialty?
Dr. Timothy Byun practices Hematology & Oncology Physician in Orange, CA.
Where does Dr. Timothy Byun practice?
Dr. Timothy Byun practices at 805 W la Veta Ave Ste 101, Orange, CA 928683928. Office phone: 7148351800.
What is Dr. Timothy Byun's NPI?
Dr. Timothy Byun's National Provider Identifier (NPI) is 1871545012, issued by NPPES.
Does Dr. Timothy Byun accept Medicare assignment?
Yes. Dr. Timothy Byun accepts Medicare assignment, meaning Medicare-allowed amounts are accepted as full payment for covered services.
What procedures does Dr. Timothy Byun commonly perform?
Top Medicare-reported procedures in 2023: Established patient office or other outpatient visit (HCPCS 99214); Complete blood cell count (red cells, white blood cell, platelets), automated test and automated differential white blood cell count (HCPCS 85025); Insertion of needle into vein for collection of blood sample (HCPCS 36415). Source: CMS Medicare Physician & Other Practitioners file.