Caitlin Welch, MD
Caitlin Welch, MD is a Pulmonary Disease Physician in Brunswick, ME, registered under NPI 1003235664. This provider registers 3 separate taxonomy codes, which usually means they practise across more than one recognised specialty.
Getting there
The practice address on file is 121 MEDICAL CENTER DR STE 3300, Brunswick, ME 04011. 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 |
|---|---|---|
| MD23575 | ME | Pulmonary Disease Physician primary |
| MD23575 | ME | Internal Medicine Physician |
| MD23575 | ME | Critical Care Medicine (Internal… |
This provider holds licence MD23575 issued in ME. A licence number in NPPES reflects what was filed at registration — it does not confirm the licence is still active today.
- Status
- Approved
- Provider type
- Practitioner - Pulmonary Disease
- PAC ID
- 0042513574
Medicare enrolment is recorded as approved under the provider type Practitioner - Pulmonary 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.
What Pulmonary Disease covers
An internist who treats diseases of the lungs and airways. The pulmonologist diagnoses and treats cancer, pneumonia, pleurisy, asthma, occupational and environmental diseases, bronchitis, sleep disorders, emphysema and other complex disorders of the lungs. NUCC Health Care Provider Taxonomy, code 207RP1001X
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 | |
|---|---|---|---|---|
| 207RP1001X | Pulmonary Disease Physician Pulmonary Disease | MD23575 | ME | primary |
| 207R00000X | Internal Medicine Physician | MD23575 | ME | |
| 207RC0200X | Critical Care Medicine (Internal Medicine) Physician Critical Care Medicine | MD23575 | ME |
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 | 1003235664 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Apr 10, 2014 |
| Last updated | May 27, 2025 |
| Status | Active |
| Sole proprietor | No |
| Credential | MD |
| Practice address |
121 MEDICAL CENTER DR STE 3300 Brunswick, ME 04011 (207) 373-6490 |
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 | 0 | 3 | 2 | 3 | 5 | 6 | 6 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 0 | 0 | 3 | 4 | 3 | 1 | 6 | 3 |
Sum = 46 · next multiple of 10 = 50 · check digit = 4 · actual last digit = 4
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.