John Merrill, M.D.
John Merrill, M.D. is a Medical Oncology Physician in Hayden, CO, registered under NPI 1801237276. 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 40515 COUNTY ROAD 69A SUITE B, Hayden, CO 81639. 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 |
|---|---|---|
| DR 0038411 | CO | Medical Oncology Physician primary |
This provider holds licence DR 0038411 issued in CO. 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 Medical Oncology covers
An internist who specializes in the diagnosis and treatment of all types of cancer and other benign and malignant tumors. This specialist decides on and administers therapy for these malignancies as well as consults with surgeons and radiotherapists on other treatments for cancer. NUCC Health Care Provider Taxonomy, code 207RX0202X
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 | 1801237276 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Jul 12, 2013 |
| Last updated | Jul 12, 2013 |
| Status | Active |
| Sole proprietor | Yes |
| Credential | M.D. |
| Practice address |
40515 COUNTY ROAD 69A SUITE B Hayden, CO 81639 (970) 276-1933 |
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 | 8 | 0 | 1 | 2 | 3 | 7 | 2 | 7 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 8 | 0 | 1 | 4 | 3 | 5 | 2 | 5 |
Sum = 54 · next multiple of 10 = 60 · 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.