Theodore Pak, MD, PHD
Theodore Pak, MD, PHD is an Infectious Disease Physician in Orange, CA, registered under NPI 1013476100. This provider registers 2 separate taxonomy codes, which usually means they practise across more than one recognised specialty.
Getting there
The practice address on file is 101 THE CITY DR S, Orange, CA 92868. We have not yet mapped what surrounds this office — parking, transit, and nearby pharmacies are added as our data collection reaches each location.
Credentials and Medicare
| Licence | State | Specialty |
|---|---|---|
| A203241 | CA | Infectious Disease Physician primary |
| 291119 | MA | Infectious Disease Physician |
| 291119 | MA | Internal Medicine Physician |
Licences are recorded in 2 states: CA, MA. Providers licensed in several states often practise near a state border or deliver telehealth across state lines.
- Status
- Approved
- Provider type
- Practitioner - Infectious Disease
- PAC ID
- 0042549099
Medicare enrolment is recorded as approved under the provider type Practitioner - Infectious Disease. This means the provider is enrolled to bill Medicare, though it does not tell you whether they are currently accepting new Medicare patients. Call the office to confirm.
Licensed in 2 states
This provider holds licences in 2 states: California and Massachusetts. The practice address on file is in Orange, CA, but a licence in another state usually means they see patients there too — either at a second location or by telehealth. If the address above is far from you, it is worth calling to ask whether they practise closer to where you live.
- Licence
- A203241
- Specialty
- Infectious Disease Physician
Licence numbers are self-reported to NPPES at registration. They do not confirm a licence is currently active, in good standing, or valid for the specialty shown — only the state board can tell you that, which is why we link to each one.
What Infectious Disease covers
An internist who deals with infectious diseases of all types and in all organ systems. Conditions requiring selective use of antibiotics call for this special skill. This physician often diagnoses and treats AIDS patients and patients with fevers which have not been explained. Infectious disease specialists may also have expertise in preventive medicine and travel medicine. NUCC Health Care Provider Taxonomy, code 207RI0200X
All registered taxonomy codes
This provider registers 3 taxonomy codes. The primary code is what appears on most claims; the others record additional recognised specialties.
| Code | Specialty | Licence | State | |
|---|---|---|---|---|
| 207RI0200X | Infectious Disease Physician Infectious Disease | A203241 | CA | primary |
| 207RI0200X | Infectious Disease Physician Infectious Disease | 291119 | MA | |
| 207R00000X | Internal Medicine Physician | 291119 | MA |
The taxonomy records how the provider classifies their own practice. It does not confirm which conditions they currently treat, whether they are accepting new patients, or which insurance they take — call the office for that.
Full NPPES record
An NPI-1 identifies a single person. It stays with the clinician for life, even if they move practice or change state, which is why the address on file can lag behind where they actually work today.
| NPI | 1013476100 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Mar 18, 2019 |
| Last updated | Jan 9, 2026 |
| Status | Active |
| Sole proprietor | No |
| Credential | MD, PHD |
| Practice address |
101 THE CITY DR S Orange, CA 92868 (714) 456-8888 |
Number check
How the check works, step by step
Every NPI carries a Luhn check digit — the same scheme used on credit cards. CMS prefixes the number with 80840 before computing it, which marks it as a US health identifier.
| Digit | 8 | 0 | 8 | 4 | 0 | 1 | 0 | 1 | 3 | 4 | 7 | 6 | 1 | 0 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 0 | 2 | 3 | 8 | 7 | 3 | 1 | 0 |
Sum = 50 · next multiple of 10 = 50 · check digit = 0 · actual last digit = 0
A valid check digit only means the number is well-formed. It does not mean the provider is licensed, active, or in good standing — those are separate questions answered by the sections above.