Charles Feng, MD
Charles Feng, MD is an Allergy & Immunology Physician in Mountain View, CA, registered under NPI 1518260306. This provider registers 2 separate taxonomy codes, which usually means they practise across more than one recognised specialty.
Getting there
The practice address on file is 701 E EL CAMINO REAL, Mountain View, CA 94040. 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 |
|---|---|---|
| A115080 | CA | Allergy & Immunology Physician primary |
| A115080 | CA | Internal Medicine Physician |
This provider holds licence A115080 issued in CA. 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 - Allergy/immunology
- PAC ID
- 6800035007
- Enrollment ID
- I20130619000536
Medicare enrolment is recorded as approved under the provider type Practitioner - Allergy/immunology. 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 Allergy & Immunology covers
An allergist-immunologist is trained in evaluation, physical and laboratory diagnosis, and management of disorders involving the immune system. Selected examples of such conditions include asthma, anaphylaxis, rhinitis, eczema, and adverse reactions to drugs, foods, and insect stings as well as immune deficiency diseases (both acquired and congenital), defects in host defense, and problems related to autoimmune disease, organ transplantation, or malignancies of the immune system. NUCC Health Care Provider Taxonomy, code 207K00000X
All registered taxonomy codes
This provider registers 2 taxonomy codes. The primary code is what appears on most claims; the others record additional recognised specialties.
| Code | Specialty | Licence | State | |
|---|---|---|---|---|
| 207K00000X | Allergy & Immunology Physician | A115080 | CA | primary |
| 207R00000X | Internal Medicine Physician | A115080 | 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 | 1518260306 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Dec 16, 2010 |
| Last updated | Sep 23, 2015 |
| Status | Active |
| Sole proprietor | No |
| Gender | Male |
| Credential | MD |
| Practice address |
701 E EL CAMINO REAL Mountain View, CA 94040 (650) 934-7888 |
| Mailing address |
2350 W. EL CAMINO REAL 2ND FLOOR Mountain View, CA 94040 |
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 | 5 | 1 | 8 | 2 | 6 | 0 | 3 | 0 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 5 | 2 | 8 | 4 | 6 | 0 | 3 | 0 |
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.