Timothy Byun, MD
NPI 1871545012 · Hematology & Oncology Physician · Orange, CA
Enrolled with Medicare as Practitioner - Hematology/Oncology · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Timothy Byun, MD is a Hematology & Oncology Physician provider in Orange, CA (NPI 1871545012).
Provider details
- NPI number
- 1871545012
- Entity type
- Individual
- Primary specialty
- Hematology & Oncology PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Male
- Sole proprietor
- No
- License
- A70195 (CA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure25% of score
20 yrs in NPPES registry
- Profile completeness25% of score
100% of core fields populated
- Practice footprint15% of score
2 documented practice locations
- Medicare service volume (vs. specialty peers)25% of score
1,142 Medicare services, 2024 (ranked within specialty)
- Open Payments transparency10% of score
Has Open Payments disclosures (2024)
Medicare volume is ranked against active providers in the same specialty. Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our .
What this provider does (Medicare)
Based on Medicare fee-for-service claims, 2024; not all care is captured.
| Service (HCPCS) | Medicare services | Typical Medicare-allowed (2024) |
|---|---|---|
| Established Patient Office Or Other Outpatient Visit With Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 457 | $137 |
| Established Patient Office Or Other Outpatient Visit With Low Level OD Decision Making, If Using Time, 20 Minutes Or More99213 | 236 | $98 |
| Subsequent Hospital Care With Moderate Levelof Medical Decision Making, If Using Time, at Least 50 Minutes99233 | 74 | $123 |
| Complete Blood Cell Count (red Cells, White Blood Cell, Platelets), Automated Test and Automated Differential White Blood Cell Count85025 | 69 | $8 |
| Insertion of Needle Into Vein for Collection of Blood Sample36415 | 67 | $9 |
| Administration of Chemotherapy Into Vein, 1 Hour Or Less96413 |
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 40 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Anastrozole | 109 | 40 |
| Enzalutamidebrand: Xtandi | 98 | 12 |
| Apixabanbrand: Eliquis | 70 | 16 |
| Prednisone | 66 | 20 |
| Dexamethasone | 63 | 18 |
| Hydroxyurea | 59 | 17 |
| Letrozole | 55 | 14 |
| Acyclovir |
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$6,726 across 235 records (Open Payments 2024)
Open Payments discloses payments and transfers of value (meals, travel, consulting, research, royalties) from drug and device makers to providers. This is a transparency signal, not a verdict — such payments are legal and common, and their presence is neither an endorsement nor a criticism. Source: CMS Open Payments, program year 2024.
Practice location
Mailing address
Additional practice locations (1)
- 1010 W La Veta Ave#200Orange, CA 92868-4300Phone: (714) 835-1800Fax: (714) 835-1811
Registry dates
- Enumerated
- 2006-05-16
- Last updated
- 2024-06-04
- Certified
- 2024-06-04
Frequently asked questions
- What is Timothy Byun's NPI number?
- Timothy Byun's National Provider Identifier (NPI) is 1871545012, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Timothy Byun's specialty?
- Timothy Byun is listed in the NPPES registry with a primary specialty of Hematology & Oncology Physician (Allopathic & Osteopathic Physicians).
- Where is Timothy Byun located?
- Timothy Byun's practice location on file with NPPES is 805 W La Veta Ave Ste 101, Orange, CA 92868-3928.
- What is Timothy Byun's phone number?
- The practice phone number listed in the NPPES registry for Timothy Byun is (714) 835-1800.
- Does Timothy Byun accept Medicare?
- Timothy Byun is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Timothy Byun's NPI active?
- Yes — Timothy Byun's NPI (1871545012) is active in the NPPES registry as of the last update on 2024-06-04.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.