Dr. Zachary Daniel Preefer, DO
- Medicare services, 2024
- 19
- Medicare patients, 2024
- 61
- Hospital affiliations
- 1
- Industry payments
- $1,873
- Medical group
- 1
- Practice address
- 2105 Forest Avenue, San Jose, CA 95128
- Practice phone
- Call (408) 947-2831
- Professional email
- Get professional email
- Personal email
- Get personal email
- Mobile number
- Get mobile number
Primary practice
O'Connor Hospital
Skilled Nursing Facility - Hospital-Based · San Jose, California
Find Dr. Preefer'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. Zachary Daniel Preefer is an anesthesiologist in San Jose, California
Dr. Preefer practices at O'Connor Hospital in San Jose, California.
Dr. Preefer's NPI, 1093202566, was assigned on April 19, 2018. Dr. Preefer graduated from Des Moines University in 2018. Dr. Preefer's California license number on file is 21899.
- NPI
- 1093202566NPI Registry (opens in a new tab)
- Medicare PAC ID
- 4981931383
- NPI enumeration date
- April 19, 2018
- NPI status
- Active
- Accepts Medicare assignment
- Yes
- Practice phone
- (408) 947-2831
- Professional email
- Get email
- Personal email
- Get email
- Mobile number
- Get number
- Sex
- Male
- Estimated age
- 34
- Medical school graduation
- 2018
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; Dmand AI Affiliation Data; and Doctors and Clinicians National Downloadable File (CMS)
Dr. Zachary Daniel Preefer practices at O'Connor Hospital in San Jose, California
Dr. Preefer's primary practice is O'Connor Hospital, at 2105 Forest Avenue, San Jose, CA 95128 in Santa Clara County. The practice phone is (408) 947-2831.
- O'Connor Hospital2105 Forest Avenue, San Jose, CA 95128 · Santa Clara CountyPhone(408) 947-2831
Source: Dmand AI Affiliation Data
Dr. Zachary Daniel Preefer is affiliated with 2 sites of care and 1 medical group
Dr. Preefer's primary practice is O'Connor Hospital in San Jose, California. Dr. Preefer is also affiliated with Santa Clara Valley Medical Center. The medical group on file is CEP America.
Sources: Dmand AI Affiliation Data; and Dmand AI Org Hierarchy Data
Dmand AI tracks the EHR system at Dr. Zachary Daniel Preefer's practice
Dmand AI tracks the electronic health record (EHR) system at each site where Dr. Preefer practices, 2 sites in all. Vendor and product names are available with a free account.
| Site | EHR vendor and product |
|---|---|
| O'Connor Hospital | 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. Zachary Daniel Preefer is one of 6,593 anesthesiologists in California
Anesthesiology is Dr. Preefer's primary specialty in the NPI Registry, under taxonomy code 207L00000X. Dmand AI has Dr. Preefer's licenses on file in 3 states: California, Washington and Massachusetts.
Specialties and state licenses
- Anesthesiology, CaliforniaPrimary
- Pain medicine (anesthesiology), Washington
- Massachusetts license
Anesthesiologists near Dr. Preefer
Counts of anesthesiologists 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. Zachary Daniel Preefer billed Medicare for 19 services in 2024
CMS data shows 19 Medicare services from Dr. Preefer across 1 procedure code in 2024, for 61 Medicare patients. Medicare paid $2,271 for them. Every service was in a facility, such as a hospital, rather than an office.
Dr. Preefer compared with the California median for anesthesiologists, 2024
- Dr. Preefer
- California median
- Medicare services
- 19vs 7274% below
- Medicare patients
- 61vs 14357% below
Medians across 5,562 anesthesiologists in California with Dmand AI profiles that report each measure.
Dr. Preefer's most billed Medicare procedure codes, 2024
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. Preefer?
Medicare shows one payer. Book a meeting to get commercial claims data for Dr. Preefer and other anesthesiologists in California.
Sources: Medicare Physician & Other Practitioners - by Provider and Service (CMS), 2024 data; and Dmand AI Peer Benchmarks
Dr. Zachary Daniel Preefer treated 61 Medicare patients in 2024, average age 72
CMS counts 61 Medicare patients who saw Dr. Preefer in 2024. The largest group is 65 to 74, with 31 patients. 75% of them have high blood pressure, and 74% have high cholesterol. 74% are also on Medicaid. Their average risk score is 1.93, where 1.00 is the Medicare average, so they are sicker than most Medicare patients.
Across all payers, Dmand AI patient panel data puts Dr. Preefer's median patient age at 62, with 60% women.
Dr. Preefer's Medicare patients by age, 2024
CMS leaves out age groups with fewer than 11 patients.
Dr. Preefer's Medicare patients by sex, 2024
- Women3151%
- Men3049%
Chronic conditions among Dr. Preefer's Medicare patients, 2024
- High blood pressure75%
- High cholesterol74%
- Diabetes64%
- Arthritis38%
- Chronic kidney disease33%
- Ischemic heart disease33%
- Atrial fibrillation23%
- Depression23%
Share of Medicare patients with each condition. A patient can have several.
Dr. Preefer's patients across all payers
Dmand AI patient panel data covers Medicare, Medicaid and commercial patients.
Patient panel by age, all payers
Median age 62
Patient panel by sex, all payers
- Women60%
- Men38%
Sources: Dmand AI Patient Panel Data; and Medicare Physician & Other Practitioners - by Provider (CMS), 2024 data
How Dr. Zachary Daniel Preefer takes part in Medicare
Dr. Preefer accepts Medicare assignment, so Medicare's approved amount is taken as full payment.
- Accepts Medicare assignment
- Yes
Source: Doctors and Clinicians National Downloadable File (CMS)
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Dr. Zachary Daniel Preefer received $1,873 in industry payments from 2022 to 2023
CMS Open Payments shows 14 general payments to Dr. Preefer from 2 drug and device companies from 2022 to 2023. Travel and lodging make up the largest share, 64% of the total. Medtronic, Inc. paid the most, $1,679.
General payments to Dr. Preefer by program year, 2022 to 2023
General payments to Dr. Preefer by kind, 2022 to 2023
- Travel and lodging$1,20564%
- Food and beverage$66836%
Companies that paid Dr. Preefer the most, 2022 to 2023
Share is of all general payments to this clinician.
Source: Open Payments (CMS), 2025 data, released July 7, 2026
Dr. Zachary Daniel Preefer graduated from Des Moines University
Dr. Preefer graduated from Des Moines University in 2018.
- Medical school
Source: Dmand AI Professional Profile Data
Dr. Zachary Daniel Preefer accepts plans from 6 insurance carriers
Dr. Preefer is in network with 6 carriers, including United Healthcare, Aspirus Health Plan and Blue Cross and Blue Shield of Kansas City. PPO plans come from the most carriers, 3. Check the plan with the practice before a visit.
- United Healthcare
- Aspirus Health Plan
- Blue Cross and Blue Shield of Kansas City
- CMS Medicare
- Elevance
- HCSC
Plan types Dr. Preefer accepts, by number of carriers
- PPO3
- Medicare2
- POS2
- EPO1
- HMO1
Source: Dmand AI Insurance Network Data
Sources for Dr. Zachary Daniel Preefer'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 | Dmand AI Affiliation Data |
| Primary practice, affiliations and health system | Dmand AI Affiliation DataDmand AI Org Hierarchy 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 DataMedicare Physician & Other Practitioners - 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) |
| Industry payments | Open Payments (CMS) (opens in a new tab) |
| 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. Zachary Daniel Preefer
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. Zachary Daniel Preefer's NPI number?
Dr. Zachary Daniel Preefer's NPI number is 1093202566. It was assigned on April 19, 2018, and it is active in the NPI Registry.
What kind of doctor is Dr. Zachary Daniel Preefer?
Dr. Zachary Daniel Preefer is an anesthesiologist in San Jose, California. The primary specialty in the NPI Registry is Anesthesiology Physician (taxonomy code 207L00000X).
Where does Dr. Zachary Daniel Preefer practice?
Dr. Preefer practices at 2105 Forest Avenue, San Jose, CA 95128. Dr. Preefer's primary practice is O'Connor Hospital in San Jose, California.
What is Dr. Zachary Daniel Preefer's office phone number?
The practice phone on file for Dr. Preefer is (408) 947-2831.
What is Dr. Zachary Daniel Preefer's medical license number?
Dr. Preefer's California license number on file is 21899, one of the licenses on file in 3 states.
Which states has Dr. Zachary Daniel Preefer been licensed in?
Dmand AI has state licenses on file for Dr. Preefer in California (2023 to 2025), Washington (2022 to 2025) and Massachusetts (2019 to 2022).
Which hospitals is Dr. Zachary Daniel Preefer affiliated with?
Dr. Preefer is affiliated with Santa Clara Valley Medical Center.
What medical group is Dr. Zachary Daniel Preefer part of?
Dr. Preefer is linked to CEP America.
Does Dr. Zachary Daniel Preefer accept Medicare?
Yes. CMS data shows Dr. Preefer billed Medicare for 19 services in 2024, and Dr. Preefer accepts Medicare assignment.
How many Medicare patients does Dr. Zachary Daniel Preefer see?
CMS counts 61 Medicare patients who saw Dr. Preefer in 2024, with an average age of 72.
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What services does Dr. Zachary Daniel Preefer bill to Medicare?
In 2024, Dr. Preefer's most billed Medicare services were anesthesia (00142).
Where did Dr. Zachary Daniel Preefer go to medical school?
Dr. Preefer graduated from Des Moines University in 2018.
Has Dr. Zachary Daniel Preefer received payments from drug or device companies?
CMS Open Payments shows $1,873 in general payments to Dr. Preefer from 2 companies from 2022 to 2023. The largest total came from Medtronic, Inc.
How long has Dr. Zachary Daniel Preefer been practicing?
Dr. Preefer graduated from medical school in 2018, 8 years ago.
What insurance does Dr. Zachary Daniel Preefer accept?
Dr. Preefer is in network with 6 carriers, including United Healthcare, Aspirus Health Plan and Blue Cross and Blue Shield of Kansas City. PPO plans come from the most carriers, 3. Check the plan with the practice before a visit.
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