John Madsen, M.D.
John Madsen, M.D. is a Gastroenterology Physician in New London, CT, registered under NPI 1144286667.
Getting there
The practice address on file is 234A BANK ST, New London, CT 06320. 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 |
|---|---|---|
| 016619 | CT | Gastroenterology Physician primary |
This provider holds licence 016619 issued in CT. A licence number in NPPES reflects what was filed at registration — it does not confirm the licence is still active today.
This NPI does not appear in the PECOS Medicare enrolment file. Providers who do not bill Medicare — or who bill only through a group's enrolment — will not appear here. It is not a sign of any problem with the registration.
What Gastroenterology covers
An internist who specializes in diagnosis and treatment of diseases of the digestive organs including the stomach, bowels, liver and gallbladder. This specialist treats conditions such as abdominal pain, ulcers, diarrhea, cancer and jaundice and performs complex diagnostic and therapeutic procedures using endoscopes to visualize internal organs. NUCC Health Care Provider Taxonomy, code 207RG0100X
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 | 1144286667 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Apr 24, 2006 |
| Last updated | Dec 20, 2012 |
| Status | Active |
| Sole proprietor | No |
| Credential | M.D. |
| Practice address |
234A BANK ST New London, CT 06320 (860) 442-0290 Fax (860) 442-2136 |
| Other identifiers |
001168194
· Medicaid (CT) |
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 | 1 | 4 | 4 | 2 | 8 | 6 | 6 | 6 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 1 | 8 | 4 | 4 | 8 | 3 | 6 | 3 |
Sum = 63 · next multiple of 10 = 70 · check digit = 7 · actual last digit = 7
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.