Dr. John S. Vassar, MD
- Medicare services, 2020
- 105
- Publications
- 3
- Industry payments
- $139
- State license
- 1
- Year NPI issued
- 2006
- Practice address
- 305 State S St, Aberdeen, SD 57401
- Practice phone
- Call (605) 622-5000
- Professional email
- Get professional email
- Personal email
- Get personal email
- Mobile number
- Get mobile number
Primary practice
Avera St Lukes Hospital
Aberdeen, South Dakota
Find Dr. Vassar'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. John S. Vassar is an anesthesiologist in Aberdeen, South Dakota
Dr. Vassar practices at Avera St Lukes Hospital in Aberdeen, South Dakota.
Dr. Vassar's NPI, 1144248295, was assigned on July 17, 2006. Dr. Vassar holds South Dakota license 5857.
- NPI
- 1144248295NPI Registry (opens in a new tab)
- NPI enumeration date
- July 17, 2006
- NPI status
- Active
- Practice phone
- (605) 622-5000
- Professional email
- Get email
- Personal email
- Get email
- Mobile number
- Get number
- Sex
- Male
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; and Dmand AI Practice Data
Dr. John S. Vassar practices at Avera St Lukes Hospital in Aberdeen, South Dakota
Dr. Vassar's primary practice is Avera St Lukes Hospital, at 305 State S St, Aberdeen, SD 57401 in Brown County. The practice phone is (605) 622-5000.
- Avera St Lukes Hospital305 State S St, Aberdeen, SD 57401 · Brown CountyPhone(605) 622-5000
Sources: NPPES NPI Registry (CMS); and Dmand AI Practice Data
Dr. John S. Vassar is affiliated with 1 site of care
Dr. Vassar's primary practice is Avera St Lukes Hospital in Aberdeen, South Dakota.
Sources: NPPES NPI Registry (CMS); and Dmand AI Practice Data
Dmand AI tracks the EHR system at Dr. John S. Vassar's practice
Dmand AI tracks the electronic health record (EHR) system at each site where Dr. Vassar practices. Vendor and product names are available with a free account.
| Site | EHR vendor and product |
|---|---|
| Avera St Lukes Hospital | Available with a free account |
Source: Dmand AI Technology Install Data
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Dr. John S. Vassar is one of 92 anesthesiologists in South Dakota
Anesthesiology is Dr. Vassar's primary specialty in the NPI Registry, under taxonomy code 207L00000X. Dr. Vassar is licensed in South Dakota.
Specialties and state licenses
- Anesthesiology, South DakotaPrimary
Anesthesiologists near Dr. Vassar
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. John S. Vassar billed Medicare for 105 services in 2020
CMS data shows 105 Medicare services from Dr. Vassar across 6 procedure codes in 2020. Medicare paid $9,506 for them. Every service was in a facility, such as a hospital, rather than an office.
Dr. Vassar's Medicare services by type, 2019 to 2020
- 2019
- 2020
- Anesthesia
- 2019: 262020: 105304%
Dr. Vassar compared with the South Dakota median for anesthesiologists, 2020
- Dr. Vassar
- South Dakota median
- Medicare services
- 105vs 30566% below
Medians across 101 anesthesiologists in South Dakota with Dmand AI profiles that report each measure.
Dr. Vassar's most billed Medicare procedure codes, 2020
CMS publishes codes billed for 11 or more Medicare patients. Each label is the code family; CPT descriptions are licensed by the AMA.
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Medicare shows one payer. Book a meeting to get commercial claims data for Dr. Vassar and other anesthesiologists in South Dakota.
Sources: Medicare Physician & Other Practitioners - by Provider and Service (CMS), 2024 data; and Dmand AI Peer Benchmarks
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Dr. John S. Vassar has 3 publications on record
Dmand AI links 3 papers to Dr. Vassar in 2024. Dr. Vassar has published most often in S D Med. Dr. Vassar's most frequent co-author is Marcus Lee Frohm, MD.
Dr. Vassar's most frequent co-authors
Recent publications by Dr. Vassar
See who Dr. Vassar researches with
Physician Network Discovery turns co-authorship, shared hospitals and shared groups into a map of who Dr. Vassar works with, so you can find a warm path to the right anesthesiologists.
Sources: PubMed (National Library of Medicine); and Dmand AI Research Linkage
Dr. John S. Vassar received $139 in industry payments in 2017
CMS Open Payments shows 2 general payments to Dr. Vassar from 2 drug and device companies in 2017. Food and beverage make up the largest share, 100% of the total. Mallinckrodt LLC paid the most, $125.
Companies that paid Dr. Vassar the most, 2017 to 2017
Share is of all general payments to this clinician.
Source: Open Payments (CMS), 2025 data, released July 7, 2026
Sources for Dr. John S. Vassar'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 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 |
| 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) |
| 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. John S. Vassar
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. John S. Vassar's NPI number?
Dr. John S. Vassar's NPI number is 1144248295. It was assigned on July 17, 2006, and it is active in the NPI Registry.
What kind of doctor is Dr. John S. Vassar?
Dr. John S. Vassar is an anesthesiologist in Aberdeen, South Dakota. The primary specialty in the NPI Registry is Anesthesiology Physician (taxonomy code 207L00000X).
Where does Dr. John S. Vassar practice?
Dr. Vassar practices at 305 State S St, Aberdeen, SD 57401. Dr. Vassar's primary practice is Avera St Lukes Hospital in Aberdeen, South Dakota.
What is Dr. John S. Vassar's office phone number?
The practice phone on file for Dr. Vassar is (605) 622-5000.
What is Dr. John S. Vassar's medical license number?
Dr. Vassar holds South Dakota license 5857.
Does Dr. John S. Vassar accept Medicare?
Yes. CMS data shows Dr. Vassar billed Medicare for 105 services in 2020.
What services does Dr. John S. Vassar bill to Medicare?
In 2020, Dr. Vassar's most billed Medicare services were anesthesia (00731), anesthesia (00790) and anesthesia (00840).
Has Dr. John S. Vassar received payments from drug or device companies?
CMS Open Payments shows $139 in general payments to Dr. Vassar from 2 companies from 2017 to 2017. The largest total came from Mallinckrodt LLC.
How long has Dr. John S. Vassar been practicing?
Dr. Vassar's NPI was assigned in 2006.
Does Dr. John S. Vassar do research?
Dmand AI links 3 publications to Dr. Vassar.
Who does Dr. John S. Vassar publish with?
Dr. Vassar's most frequent co-authors are Marcus Lee Frohm, MD (1 shared paper).
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