Carl Geahchan, M.D
Carl Geahchan, M.D is a Critical Care Medicine (Anesthesiology) Physician in Boston, MA, registered under NPI 1902272776. NPPES records them as a sole proprietor, meaning the practice is not incorporated as a separate legal entity.
Getting there
The practice address on file is 800 WASHINGTON ST DEPARTMENT OF SURGERY, Boston, MA 02111. 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 |
|---|---|---|
| 287954 | MA | Critical Care Medicine (Anesthesiology)… primary |
This provider holds licence 287954 issued in MA. 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 - Anesthesiology
- PAC ID
- 2769771716
- Enrollment ID
- I20211022000525
Medicare enrolment is recorded as approved under the provider type Practitioner - Anesthesiology. Being enrolled means the provider can bill Medicare; it does not tell you whether they are currently accepting new Medicare patients. Call the office to confirm.
What Critical Care Medicine covers
An anesthesiologist, who specializes in critical care medicine diagnoses, treats and supports patients with multiple organ dysfunction. This specialist may have administrative responsibilities for intensive care units and may also facilitate and coordinate patient care among the primary physician, the critical care staff and other specialists. NUCC Health Care Provider Taxonomy, code 207LC0200X
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 | 1902272776 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Aug 17, 2015 |
| Last updated | Feb 19, 2024 |
| Status | Active |
| Sole proprietor | Yes |
| Credential | M.D |
| Practice address |
800 WASHINGTON ST DEPARTMENT OF SURGERY Boston, MA 02111 (617) 636-8003 |
| Mailing address |
120 KINGSTON ST UNIT 2001 Boston, MA 02111 |
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 | 9 | 0 | 2 | 2 | 7 | 2 | 7 | 7 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 9 | 0 | 2 | 4 | 7 | 4 | 7 | 5 |
Sum = 64 · next multiple of 10 = 70 · check digit = 6 · actual last digit = 6
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.