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Active NPI 1306835723 Individual Practitioner Male Practitioner

Dr. William Norman Hamstra , DO

Surgery • San Ramon, CA

✓ Accepts Medicare Assignment
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This profile is compiled from official public domain records provided by CMS and the NPPES registry. TRUE-MEDINFO is an independent reference directory and does not provide medical advice, diagnosis, or treatment recommendations. Always consult a licensed medical professional for personal health decisions.

Professional Overview & Biography Verified Profile Summary

Dr. William Hamstra, DO is a registered Surgery practitioner in San Ramon, CA. With approximately 40 years of clinical practice since graduating from Oklahoma State University College Of Osteopathic Medicine in 1986, Dr. Hamstra provides healthcare services at the registered practice location at 2305 CAMINO RAMON.

Dr. Hamstra is affiliated with Permanente Medical Group Inc and accepts Medicare assignment.

Frequently performed procedures and clinical services include established patient outpatient office visit, new patient outpatient office visit. Full Medicare procedure pricing transparency rates and service volume details are listed on this profile.

Practice Location & Contact Primary Location

Practice Address

2305 Camino Ramon
Suite 217

San Ramon, CA 945831396

Telephone 9254470660
Fax 9254437506
Associated Practice Facility / Clinic
🏢 Angela Pourghassemi Dmd, Inc. Facility NPI 1669579843

Medicare Profile & Education

Medical School

Oklahoma State University College Of Osteopathic Medicine

Graduation Year

1986

Medicare Assignment

✓ Accepts Assignment

Telehealth Flag

In-Person Only

Specialty Benchmarks & Practice Insights

Comparative analytics for Surgery in San Ramon, CA

Senior Veteran Specialist (>20 Yrs)
Practitioner Clinical Experience
40 Yrs +9.5 yrs vs City Avg
City Avg: 30.5 Yrs
State Avg: 27.4 Yrs
Regional Practice Density
6 Specialists

Practicing in San Ramon, CA (3346 Statewide)

Telehealth Adoption Rate
16.7% Regional Adoption

In-Person Office Visits Only

Medicare Pricing Discount
49.8% Avg Savings

Under CMS Medicare Fee Schedule vs Standard Submitted Charges

Clinical Seniority & Experience Comparison

Dr. Hamstra (40 Years) 40 Yrs
San Ramon Specialty Average (30.5 Years) 30.5 Yrs

Performed Procedures & Service Volume

Top Medicare Part B procedures performed by this practitioner

CMS Official Data (2017)
HCPCS Code & Description Services Patients Submitted Charge Medicare Allowed
99213 Established patient office or other outpatient visit, typically 15 minutes
27 20 $160.25 $81.24
99203 New patient office or other outpatient visit with low level of medical decision making, if using time, 30 minutes or more
18 18 $237.80 $119.06
99204 New patient office or other outpatient visit with moderate level of medical decision making, if using time, 45 minutes or more
11 11 $358.95 $179.39

Medical Specialties & State Licenses

Surgery Primary Specialty

NUCC Taxonomy Code: 208600000X

State License CA 20A5413

A general surgeon has expertise related to the diagnosis - preoperative, operative and postoperative management - and management of complications of surgical conditions in the following areas: alimentary tract; abdomen; breast, skin and soft tissue; endocrine system; head and neck surgery; pediatric surgery; surgical critical care; surgical oncology; trauma and burns; and vascular surgery. General surgeons increasingly provide care through the use of minimally invasive and endoscopic techniques. Many general surgeons also possess expertise in transplantation surgery, plastic surgery and cardiothoracic surgery.

Additional State Medicaid & Healthcare Payer Identifiers

Medicaid State Provider ID
00AX54131 (CA)

Hospital & Practice Group Affiliations

Permanente Medical Group Inc

7373 W Lane, Stockton, CA 952103377

Phone: 2094762000

Practice Associates & Co-Workers

Healthcare professionals and specialists practicing at this location or sharing practice phone/fax

12 Associated Practitioners
Dr. Mahmood Kazemi , MD

Internal Medicine - Endocrinology, Diabetes & Metabolism

NPI 1104892264

Doctor of Medicine (M.D.)

NPI 1144245580

Doctor of Medicine (M.D.)

NPI 1174791677

Doctor of Medicine (M.D.)

NPI 1245238682

Doctor of Medicine (M.D.)

NPI 1275607848

Doctor of Osteopathic Medicine (D.O.)

NPI 1316979602

Doctor of Medicine (M.D.)

Career & Practice History Timeline

Chronological log of verified NPI updates, location relocations, credentials, and registry changes

6 Historical Events
NPI Profile Active July 01, 2014

NPI status registered as active in NPPES database

📍
Updated Practice Location July 01, 2014

Registered at 2305 CAMINO RAMON, SUITE 217, SAN RAMON, CA 945831396 (Tel: 9254470660)

📍
Updated Business Mailing Address July 01, 2014

Registered at 2305 CAMINO RAMON, SUITE 217, SAN RAMON, CA 945831396 (Tel: 9254470660)

👤
Provider Name / Credentials Updated July 01, 2014

Recorded as WILLIAM HAMSTRA, D.O.

🎓
Medical Taxonomy / Specialty Registered (Primary Specialty) July 01, 2014

Surgery (License #20A5413 in CA)

🟢
Initial NPI Registration & Enumeration October 18, 2005

First registered as active Individual Practitioner in NPPES Database.

Patient & Community Reviews

Verified patient ratings, medical care experiences, and facility photos

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NPI Administrative Meta

NPI Number: 1306835723
Entity Type:
Individual Provider Physician, Nurse Practitioner, or Solo Healthcare Professional (Type 1 NPI)
Enumeration Date: October 18, 2005
Last Update: February 11, 2022
Sole Proprietor: Yes

Mailing Address

2305 Camino Ramon, Suite 217

San Ramon, CA 945831396

Phone: 9254470660

Public Domain Record This profile contains public domain information published by CMS and NPPES under the Freedom of Information Act (FOIA).
⚠️ Medical Disclaimer

This directory listing is for informational purposes only and does not constitute medical advice, diagnosis, or physician endorsement. If you are experiencing a medical emergency, please call 911 immediately.