Dr. William Norman Hamstra, DO
- Medicare services, 2017
- 56
- Part D claims, 2024
- 75
- Publications
- 1
- Industry payments
- $9,773
- Affiliated sites
- 1
- Practice address
- 7373 West Ln, Stockton, CA 95210
- Practice phone
- Call (209) 476-2000
- Professional email
- Get professional email
- Personal email
- Get personal email
- Mobile number
- Get mobile number
Primary practice
Permanente Medical Group Inc
Stockton, California
Find Dr. Hamstra's professional email, personal email and mobile number
Dmand AI checks each channel through healthcare-specific waterfall enrichment. See what is on file with a free account, with practice phones, licenses and affiliations.
Dr. William Norman Hamstra is a general surgeon in Stockton, California
Dr. Hamstra practices at Permanente Medical Group Inc in Stockton, California.
Dr. Hamstra's NPI, 1306835723, was assigned on October 18, 2005. Dr. Hamstra graduated from Oklahoma State University College Of Osteopathic Medicine in 1986. Dr. Hamstra holds California license 20A5413.
- NPI
- 1306835723NPI Registry (opens in a new tab)
- Medicare PAC ID
- 8628005311
- NPI enumeration date
- October 18, 2005
- NPI status
- Active
- Accepts Medicare assignment
- Yes
- Practice phone
- (209) 476-2000
- Professional email
- Get email
- Personal email
- Get email
- Mobile number
- Get number
- Sex
- Male
- Estimated age
- 66
- Medical school graduation
- 1986
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; Dmand AI Practice Data; and Doctors and Clinicians National Downloadable File (CMS)
Dr. William Norman Hamstra practices at Permanente Medical Group Inc in Stockton, California
Dr. Hamstra's primary practice is Permanente Medical Group Inc, at 7373 West Ln, Stockton, CA 95210 in San Joaquin County. The practice phone is (209) 476-2000.
- Permanente Medical Group Inc7373 West Ln, Stockton, CA 95210 · San Joaquin CountyPhone(209) 476-2000
Sources: NPPES NPI Registry (CMS); and Dmand AI Practice Data
Dr. William Norman Hamstra is affiliated with 2 sites of care and 1 medical group
Dr. Hamstra's primary practice is Permanente Medical Group Inc in Stockton, California. The medical group on file is The Permanente Medical Group, Inc. Dmand AI also links Dr. Hamstra to 1 more group practice or clinic, named with a free account.
Sources: NPPES NPI Registry (CMS); Dmand AI Practice Data; and Dmand AI Affiliation Data
Dmand AI tracks the EHR system at Dr. William Norman Hamstra's practice
Dmand AI tracks the electronic health record (EHR) system at each site where Dr. Hamstra practices. Vendor and product names are available with a free account.
| Site | EHR vendor and product |
|---|---|
| Permanente Medical Group Inc | Available with a free account |
| +1 more affiliated site | Available with a free account |
Source: Dmand AI Technology Install Data
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Dr. William Norman Hamstra is one of 2,926 general surgeons in California
Surgery is Dr. Hamstra's primary specialty in the NPI Registry, under taxonomy code 208600000X. Dmand AI has Dr. Hamstra's licenses on file in 2 states: California and Michigan.
Specialties and state licenses
- Surgery, CaliforniaPrimary
- Michigan license
General surgeons near Dr. Hamstra
Counts of general surgeons with a Dmand AI profile, by place and practice. Each opens the list.
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; and Dmand AI Peer Benchmarks
Dr. William Norman Hamstra billed Medicare for 56 services in 2017
CMS data shows 56 Medicare services from Dr. Hamstra across 3 procedure codes in 2017, all of them office visits. Medicare paid $4,861 for them. Every service was in an office.
Dr. Hamstra's Medicare services by type, 2016 to 2017
- 2016
- 2017
- Office and hospital visits
- 2016: 692017: 5619%
Dr. Hamstra compared with the California median for general surgeons, 2017
- Dr. Hamstra
- California median
- Medicare services
- 56vs 16666% below
- Part D claims
- 44vs 3429% above
Medians across 2,606 general surgeons in California with Dmand AI profiles that report each measure.
Dr. Hamstra's most billed Medicare procedure codes, 2017
CMS publishes codes billed for 11 or more Medicare patients. Each label is the code family; CPT descriptions are licensed by the AMA.
Need commercial claims for Dr. Hamstra?
Medicare shows one payer. Book a meeting to get commercial claims data for Dr. Hamstra and other general surgeons in California.
Sources: Medicare Physician & Other Practitioners - by Provider and Service (CMS), 2024 data; and Dmand AI Peer Benchmarks
Dr. William Norman Hamstra's patients have a median age of 53
Across all payers, Dmand AI patient panel data puts Dr. Hamstra's median patient age at 53, with 59% women.
Dr. Hamstra's patients across all payers
Dmand AI patient panel data covers Medicare, Medicaid and commercial patients.
Patient panel by age, all payers
Median age 53
Patient panel by sex, all payers
- Women59%
- Men41%
Source: Dmand AI Patient Panel Data
Dr. William Norman Hamstra wrote 75 Medicare Part D claims in 2024
In 2024, Dr. Hamstra wrote 75 Medicare Part D claims for 40 patients. 96% of them were for generic drugs. CMS names the drug for 44 of them, across 2 drugs with 11 or more claims each, at $326 in total drug cost. In 2022, CMS named 42 claims across 2 drugs.
Dr. Hamstra's Part D claims by kind of drug, 2024
- Generic72 claims96%
- Brand-name and other3 claims4%
Dr. Hamstra's most prescribed drugs by claims, 2024
CMS names a drug when it has 11 or more claims. Share is of the claims for drugs CMS names.
Drug classes CMS tracks in Dr. Hamstra's Part D claims, 2024
- Opioids43%32 of 75 claims
Share of all Part D claims for each drug class CMS reports on. Classes with no claims are left out.
Part D claims for drugs CMS names, 2022 to 2024
- 2022
- 2024
- Claims for drugs CMS names
- 2022: 422024: 445%
Drugs named by CMS: 2 in 2024, 2 in 2022.
Sources: Medicare Part D Prescribers - by Provider and Drug (CMS), 2024 data, released May 6, 2026; and Medicare Part D Prescribers - by Provider (CMS), 2024 data
How Dr. William Norman Hamstra takes part in Medicare
Dr. Hamstra accepts Medicare assignment, so Medicare's approved amount is taken as full payment.
- Accepts Medicare assignment
- Yes
Melanoma (skin cancer) excision: 1 to 10 procedures (CMS shows small counts as a range)
Sources: Doctors and Clinicians National Downloadable File (CMS); and Doctors and Clinicians Utilization Data (CMS)
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Dr. William Norman Hamstra has 1 publication on record
Dmand AI links 1 paper to Dr. Hamstra.
Recent publications by Dr. Hamstra
See who Dr. Hamstra researches with
Physician Network Discovery turns co-authorship, shared hospitals and shared groups into a map of who Dr. Hamstra works with, so you can find a warm path to the right general surgeons.
Sources: PubMed (National Library of Medicine); and Dmand AI Research Linkage
Dr. William Norman Hamstra received $9,773 in industry payments from 2016 to 2022
CMS Open Payments shows 30 general payments to Dr. Hamstra from 7 drug and device companies from 2016 to 2022. Education make up the largest share, 41% of the total. Intuitive Surgical, Inc. paid the most, $5,811.
General payments to Dr. Hamstra by program year, 2016 to 2022
General payments to Dr. Hamstra by kind, 2016 to 2022
- Education$4,00041%
- Consulting fees$2,45025%
- Travel and lodging$2,36724%
- Food and beverage$95610%
Companies that paid Dr. Hamstra the most, 2016 to 2022
Share is of all general payments to this clinician.
Source: Open Payments (CMS), 2025 data, released July 7, 2026
Dr. William Norman Hamstra has 1 award and honors on record
Dmand AI lists 1 award for Dr. Hamstra, most recently CMS Stage 1 EHR in 2013.
Awards and honors for Dr. Hamstra
- 2013
- CMS Stage 1 EHR
Source: Dmand AI Professional Profile Data
Dr. William Norman Hamstra graduated from Oklahoma State University College Of Osteopathic Medicine
Dr. Hamstra graduated from Oklahoma State University College Of Osteopathic Medicine in 1986. Dr. Hamstra is a member of ACOS, ACS, AOA, ASMBS, CMA and CMDA.
- Medical school
Source: Dmand AI Professional Profile Data
Dr. William Norman Hamstra accepts plans from 4 insurance carriers
Dr. Hamstra is in network with 4 carriers, including Kaiser Permanente, Blue Cross Blue Shield of Massachusetts and HCSC. Medicare plans come from the most carriers, 3. Check the plan with the practice before a visit.
- Kaiser Permanente
- Blue Cross Blue Shield of Massachusetts
- HCSC
- CMS Medicare
Plan types Dr. Hamstra accepts, by number of carriers
- Medicare3
- PPO2
- EPO1
- HMO1
- POS1
Source: Dmand AI Insurance Network Data
Sources for Dr. William Norman Hamstra's profile data
| Data on this page | Source |
|---|---|
| NPI, name, sex, specialty and licenses | NPPES NPI Registry (CMS) (opens in a new tab)Dmand AI Professional Profile Data |
| Practice locations and phone | NPPES NPI Registry (CMS) (opens in a new tab)Dmand AI Practice Data |
| Primary practice, affiliations and health system | NPPES NPI Registry (CMS) (opens in a new tab)Dmand AI Practice DataDmand AI Affiliation Data |
| Medicare services and procedure codes | Medicare Physician & Other Practitioners - by Provider and Service (CMS) (opens in a new tab) |
| State medians for the same specialty | Dmand AI Peer Benchmarks |
| Medicare patients and the all-payer patient panel | Dmand AI Patient Panel Data |
| Part D prescribing | Medicare Part D Prescribers - by Provider and Drug (CMS) (opens in a new tab)Medicare Part D Prescribers - by Provider (CMS) (opens in a new tab) |
| MIPS scores, telehealth, assignment and procedure percentiles | Doctors and Clinicians National Downloadable File (CMS) (opens in a new tab)Doctors and Clinicians Utilization Data (CMS) (opens in a new tab) |
| Publications, topics and co-authors | PubMed (National Library of Medicine) (opens in a new tab)Dmand AI Research Linkage |
| Industry payments | Open Payments (CMS) (opens in a new tab) |
| Awards and committee roles | Dmand AI Professional Profile Data |
| Training, board certification and memberships | Dmand AI Professional Profile Data |
| Insurance carriers and plan types | Dmand AI Insurance Network Data |
| EHR at each practice site | Dmand AI Technology Install Data |
| Similar physicians | Dmand AI Affiliation Data |
Data last refreshed October 2026Report an inaccuracyRemove my information
FAQ
Frequently asked questions about Dr. William Norman Hamstra
Spotted something out of date? Email hello@dmand.ai and we will check the record. Contact details live in the free trial.
What is Dr. William Norman Hamstra's NPI number?
Dr. William Norman Hamstra's NPI number is 1306835723. It was assigned on October 18, 2005, and it is active in the NPI Registry.
What kind of doctor is Dr. William Norman Hamstra?
Dr. William Norman Hamstra is a general surgeon in Stockton, California. The primary specialty in the NPI Registry is Surgery Physician (taxonomy code 208600000X).
Where does Dr. William Norman Hamstra practice?
Dr. Hamstra practices at 7373 West Ln, Stockton, CA 95210. Dr. Hamstra's primary practice is Permanente Medical Group Inc in Stockton, California. Dmand AI also links Dr. Hamstra to 1 group practice or clinic.
What is Dr. William Norman Hamstra's office phone number?
The practice phone on file for Dr. Hamstra is (209) 476-2000.
What is Dr. William Norman Hamstra's medical license number?
Dr. Hamstra holds California license 20A5413, one of the licenses on file in 2 states.
Which states has Dr. William Norman Hamstra been licensed in?
Dmand AI has state licenses on file for Dr. Hamstra in California (1987 to 2026) and Michigan (1987 to 1991).
What medical group is Dr. William Norman Hamstra part of?
Dr. Hamstra is linked to The Permanente Medical Group, Inc.
Does Dr. William Norman Hamstra accept Medicare?
Yes. CMS data shows Dr. Hamstra billed Medicare for 56 services in 2017, and Dr. Hamstra accepts Medicare assignment.
What services does Dr. William Norman Hamstra bill to Medicare?
In 2017, Dr. Hamstra's most billed Medicare services were office visit, established patient (99213), office visit, new patient (99203) and office visit, new patient (99204).
Where did Dr. William Norman Hamstra go to medical school?
Dr. Hamstra graduated from Oklahoma State University College Of Osteopathic Medicine in 1986.
Show 5 more questionsShow fewer questions
What drugs does Dr. William Norman Hamstra prescribe most?
In 2024 Medicare Part D data, Dr. Hamstra's most prescribed drugs by claims were Oxycodone HCl and Ibuprofen.
Has Dr. William Norman Hamstra received payments from drug or device companies?
CMS Open Payments shows $9,773 in general payments to Dr. Hamstra from 7 companies from 2016 to 2022. The largest total came from Intuitive Surgical, Inc.
How long has Dr. William Norman Hamstra been practicing?
Dr. Hamstra graduated from medical school in 1986, 40 years ago.
Does Dr. William Norman Hamstra do research?
Dmand AI links 1 publication to Dr. Hamstra.
What insurance does Dr. William Norman Hamstra accept?
Dr. Hamstra is in network with 4 carriers, including Kaiser Permanente, Blue Cross Blue Shield of Massachusetts and HCSC. Medicare plans come from the most carriers, 3. Check the plan with the practice before a visit.
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