Doug Johnson
Doug Johnson is a provider specialising in General Practice Dentistry in Iowa City, IA, registered under NPI 1639575855. This provider registers 2 separate taxonomy codes, which usually means they practise across more than one recognised specialty. 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 801 NEWTON RD, Iowa City, IA 52242. 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 |
|---|---|---|
| D14139 | MN | General Practice Dentistry |
| DDS-10255 | IA | General Practice Dentistry primary |
| 63908 | CA | Dentist |
Licences are recorded in 3 states: MN, IA, CA. Providers licensed in several states often practise near a state border or deliver telehealth across state lines.
- Status
- Approved
- Provider type
- Order And Referring Only - Dentist
- PAC ID
- 6800103045
- Enrollment ID
- I20150921000604
Medicare enrolment is recorded as approved under the provider type Order And Referring Only - Dentist. 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.
Licensed in 3 states
This provider holds licences in 3 states: California, Iowa and Minnesota. The practice address on file is in Iowa City, IA, 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
- DDS-10255
- Specialty
- General Practice Dentistry
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 General Practice covers
A general dentist is the primary dental care provider for patients of all ages. The general dentist is responsible for the diagnosis, treatment, management and overall coordination of services related to patients' oral health needs. NUCC Health Care Provider Taxonomy, code 1223G0001X
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 | |
|---|---|---|---|---|
| 1223G0001X | General Practice Dentistry General Practice | D14139 | MN | |
| 1223G0001X | General Practice Dentistry General Practice | DDS-10255 | IA | primary |
| 122300000X | Dentist | 63908 | CA |
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 | 1639575855 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Nov 16, 2014 |
| Last updated | Oct 24, 2025 |
| Status | Active |
| Sole proprietor | Yes |
| Gender | Male |
| Practice address |
801 NEWTON RD Iowa City, IA 52242 (319) 335-7499 |
| Mailing address |
2920 SILVER OAK TRL Marion, IA 52302 |
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 | 6 | 3 | 9 | 5 | 7 | 5 | 8 | 5 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 6 | 6 | 9 | 1 | 7 | 1 | 8 | 1 |
Sum = 65 · next multiple of 10 = 70 · check digit = 5 · actual last digit = 5
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.