Provider records sourced from NPPES (CMS National Plan & Provider Enumeration System). Data current as of August 10, 2026.
NPIDirectory

Dr. Kenneth Sanford Blumenfeld, MD

Individual provider Specialist · NPI 1235158254

Dr. Kenneth Sanford Blumenfeld, MD practises Neurosurgery in San Jose, California. Graduated from Johns Hopkins University School of Medicine in 1986, 40 years ago. Practices with Sutter Bay Medical Foundation, a 3,762-clinician group, accepts Medicare assignment and offers telehealth. Licensed in California.

Years since qualifying
40
Trained at
Johns Hopkins University School of Medicine
Licensed in
CA
In the registry since
2006
What do these letters mean?
MD — Doctor of Medicine
A physician who completed allopathic medical school.

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Practice location Address checks out

2577 Samaritan Dr Ste 710
San Jose, CA 95124-4100 Not confirmed with CMS for 14 years — call before visiting
Phone: (408) 358-0133
Fax: (408) 358-8134
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Specialist (primary) Taxonomy 174400000X · Licence A50900 (CA)

Record details

NPI number1235158254
Entity typeIndividual (Type 1)
GenderMale
Credentials MD
Sole proprietorYes
NPI enumeratedJuly 19, 2006
Last updated in NPPESAugust 21, 2012

Medicare enrollment

From the CMS Doctors & Clinicians file — this clinician is enrolled in Medicare.

Medicare specialtyNEUROSURGERY
Medical schoolJOHNS HOPKINS UNIVERSITY SCHOOL OF MEDICINE
Graduated 1986 (40 years in practice)
Group practice Sutter Bay Medical Foundation — 3762 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount
TelehealthOffers telehealth services
Practice locations4 on file with Medicare

Procedures

From CMS Care Compare, which counts the procedures a clinician billed to Original Medicare and Medicare Advantage over a recent 12-month period. CMS reports a fixed list of common procedures, so this is not everything the clinician does. Counts of 10 or fewer are given as a range, because CMS withholds small numbers.

Laminectomy or laminotomy (partial removal of spine bones) 47 times · 75th percentile
Spinal fusion 53 times · 57th percentile

The percentile compares how often this clinician performed the procedure with other clinicians who performed it, as CMS calculates it. It measures volume, not outcomes or skill.

Medicare patients and services, 2024

From the CMS Medicare Physician & Other Practitioners file for calendar year 2024. It counts Original Medicare patients only, so a practice that mostly sees Medicare Advantage or privately insured patients looks smaller here than it is.

Medicare patients265
Services billed 531 a service is one billed item, such as a visit, a test or a procedure
Average patient age76

Dollar amounts are not shown. What Medicare pays a practice is gross billings, before staff, premises and tax and including the cost of any drugs it administers, so it is not what a clinician earns.

Practises at

Facilities the CMS Facility Affiliation file lists for this clinician.

Colleagues at Sutter Bay Medical Foundation

Clinicians the CMS Doctors & Clinicians file lists under the same group practice. CMS counts 3762 clinicians in the practice; 12 are shown here.

Other providers in San Jose