Kathryn Joanne Hallsten, M.D.
Internal Medicine Physician · Portola Valley, CA
Kathryn Joanne Hallsten, M.D. is an internal medicine physician with a practice address in Portola Valley, California, and NPI 1184750861, issued on Feb 26, 2007. Check the license (California G60511, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Kathryn Joanne Hallsten
- Credential
- M.D.
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- G60511 CA
Self-reported in NPPES; status is on the state search - Practice location
- 130 Portola RD, Portola Valley, CA 94028
- Phone
- (650) 385-1970
- Enumerated
- Feb 26, 2007
- Record last updated
- Jun 4, 2013 (not updated in 13 years: call before relying on the address or phone)
- Fax
- (650) 851-9701
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 17,696 in California → Look up another NPI →
Verify Kathryn Joanne Hallsten in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license G60511Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
99% fewer Medicare Part D claims than the average internal medicine physician in 2024
32 Medicare Part D claims, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D.
Source: CMS Medicare Part D Prescribers by Provider and Drug, 2024 (data.cms.gov). Part D covers prescriptions for Medicare patients only; drugs with fewer than 11 claims are not published.
Kathryn Joanne Hallsten among 17,696 internal medicine physician records in California
Kathryn Joanne Hallsten, M.D. is one of 17,696 internal medicine physician records with a practice address in California. 79% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2007, is newer than 44% of them.
- NPI issued2007 · 44% of these records are older, 44% newer
- In a Medicare fileYes · 79% of these records are
- In the CMS Doctors and Clinicians fileNo · 63% of these records are
- Record last updated2013 · 61% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207R00000X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
6 internal medicine physician records list a practice address in Portola Valley
They are 6 of the 84 NPPES records with a practice address in Portola Valley, and 17,696 internal medicine physician records in California.
All 17,696 in California → Every provider in Portola Valley → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- Sylvia Friedberg, M.D.Portola Valley, CA 940281396886925
- Rebecca LongPortola Valley, CA 940281639007172
- Emma Morton-Bours, M.D.Portola Valley, CA 940281316003528
- Gerard Sarnat, M.D.Portola Valley, CA 940281750658415
- Ning Tang, M.D.Portola Valley, CA 940281790806131
- Isha AbdullahAtherton, CA 940271922231737
- Harlan Matles, M.D.Menlo Park, CA 940271164423604
- Fatima Tehranchi, M.DAtherton, CA 940271366457293
Common questions
What is Kathryn Joanne Hallsten, M.D.'s NPI number?
Kathryn Joanne Hallsten, M.D.'s National Provider Identifier (NPI) is 1184750861, issued on Feb 26, 2007. An NPI identifies a provider in billing; it is not a license.
Where is Kathryn Joanne Hallsten, M.D. located?
The NPPES record lists a practice address at 130 Portola RD, Portola Valley, CA, 94028. Phone: (650) 385-1970. Providers update this record themselves, so call before visiting.
How can I verify Kathryn Joanne Hallsten, M.D.'s license?
NPPES lists California license number G60511, as entered by the provider. Search the Medical Board of California at https://www.mbc.ca.gov/License-Verification/default.aspx. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Kathryn Joanne Hallsten, M.D. prescribe under Medicare Part D?
In 2024, Kathryn Joanne Hallsten, M.D. had 32 Medicare Part D claims; the average among internal medicine physician prescribers was 3,176. Part D covers Medicare prescriptions only.
Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 2026 (NPPES files on CMS.gov); NUCC Health Care Provider Taxonomy. Medicare files from data.cms.gov. An NPI identifies who bills; it is not a license.
Figures on PlainDoctor are read from the federal files each page names (CMS NPPES, Medicare Part D, MIPS, Open Payments; the HHS-OIG exclusion list only as counts) and from Census population estimates, with the file date shown beside them. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of Aug 9, 2026.