Robert Mass, MD
NPI 1386086460 · Hematology & Oncology Physician · Mill Valley, CA
Robert Mass, MD is a Hematology & Oncology Physician provider in Mill Valley, CA (NPI 1386086460).
Provider details
- NPI number
- 1386086460
- Entity type
- Individual
- Primary specialty
- Hematology & Oncology PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Male
- Sole proprietor
- Yes
- License
- G50060 (CA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure38% of score
12 yrs in NPPES registry
- Profile completeness38% of score
100% of core fields populated
- Practice footprint23% of score
1 documented practice location
Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our methodology.
Practice location
Mailing address
Registry dates
- Enumerated
- 2013-07-18
- Last updated
- 2013-07-18
Frequently asked questions
- What is Robert Mass's NPI number?
- Robert Mass's National Provider Identifier (NPI) is 1386086460, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Robert Mass's specialty?
- Robert Mass is listed in the NPPES registry with a primary specialty of Hematology & Oncology Physician (Allopathic & Osteopathic Physicians).
- Where is Robert Mass located?
- Robert Mass's practice location on file with NPPES is 106 Elinor Ave, Mill Valley, CA 94941-1220.
- What is Robert Mass's phone number?
- The practice phone number listed in the NPPES registry for Robert Mass is (415) 497-2225.
- Is Robert Mass's NPI active?
- Yes — Robert Mass's NPI (1386086460) is active in the NPPES registry as of the last update on 2013-07-18.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.