Timothy Hsieh, MD
NPI 1821157405 · Endocrinology, Diabetes & Metabolism Physician · Los Angeles, CA
Enrolled with Medicare as Practitioner - Internal Medicine · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Timothy Hsieh, MD is a Endocrinology, Diabetes & Metabolism Physician provider in Los Angeles, CA (NPI 1821157405).
Provider details
- NPI number
- 1821157405
- Entity type
- Individual
- Primary specialty
- Endocrinology, Diabetes & Metabolism PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Male
- Sole proprietor
- No
- License
- G71934 (CA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure28% of score
19 yrs in NPPES registry
- Profile completeness28% of score
100% of core fields populated
- Practice footprint17% of score
1 documented practice location
- Medicare service volume (vs. specialty peers)28% of score
19 Medicare services, 2024 (ranked within specialty)
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 methodology.
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 | 19 | $139 |
Typical Medicare-allowed amounts for these services range $139–$139 (2024). The Medicare-allowed amount is what Medicare recognizes for a service under fee-for-service — a reference figure for 2024, not a price quote and not what you would be billed. Medicare Part B covers roughly an eighth of all NPIs (65+ skew); services with fewer than 11 beneficiaries are suppressed by CMS. Source: CMS Medicare Physician & Other Practitioners, by Provider & Service.
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 53 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Levothyroxine Sodium | 900 | 265 |
| Methimazole | 260 | 88 |
| Insulin Nph Human Isophanebrand: Humulin N | 147 | 54 |
| Insulin Glargine-Yfgn | 129 | 49 |
| Semaglutidebrand: Ozempic | 126 | 17 |
| Pen Needle, Diabeticbrand: Nano 2nd Gen Pen Needle | 122 | 51 |
| Insulin Regular, Humanbrand: Humulin R |
Practice location
Mailing address
Registry dates
- Enumerated
- 2006-12-08
- Last updated
- 2021-11-29
Frequently asked questions
- What is Timothy Hsieh's NPI number?
- Timothy Hsieh's National Provider Identifier (NPI) is 1821157405, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Timothy Hsieh's specialty?
- Timothy Hsieh is listed in the NPPES registry with a primary specialty of Endocrinology, Diabetes & Metabolism Physician (Allopathic & Osteopathic Physicians).
- Where is Timothy Hsieh located?
- Timothy Hsieh's practice location on file with NPPES is 6041 Cadillac Ave, Los Angeles, CA 90034-1702.
- What is Timothy Hsieh's phone number?
- The practice phone number listed in the NPPES registry for Timothy Hsieh is (323) 857-2000.
- Does Timothy Hsieh accept Medicare?
- Timothy Hsieh is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Timothy Hsieh's NPI active?
- Yes — Timothy Hsieh's NPI (1821157405) is active in the NPPES registry as of the last update on 2021-11-29.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.