AdhesivenessAgglutination TestsAntigens, Bacterial
Dr. Walter S. Tjoa, MD
NPI1801955463
- Part D claims, 2022
- 84
- Publications
- 2
- Hospital affiliations
- 1
- Industry payments
- $211
- Medical group
- 1
- Practice address
- 9961 Sierra Ave, Fontana, CA 92335
- Practice phone
- Call (909) 427-5000
- Professional email
- Get professional email
- Personal email
- Get personal email
- Mobile number
- Get mobile number
Primary practice
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Dr. Walter S. Tjoa is a dermatologist in Fontana, California
Dr. Tjoa practices at Fontana Medical Center in Fontana, California, part of Kaiser Permanente.
Dr. Tjoa's NPI, 1801955463, was assigned on December 8, 2006. Dr. Tjoa graduated from Catholic University of Leuven in 1978. Dr. Tjoa's California license number on file is C42142.
NPI and contact details
- NPI
- 1801955463NPI Registry (opens in a new tab)
- NPI enumeration date
- December 8, 2006
- NPI status
- Active
- Practice phone
- (909) 427-5000
- Professional email
- Get email
- Personal email
- Get email
- Mobile number
- Get number
- Sex
- Male
- Estimated age
- 74
- Medical school graduation
- 1978
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; Dmand AI Affiliation Data; and Doctors and Clinicians National Downloadable File (CMS)
Dr. Walter S. Tjoa practices at Fontana Medical Center in Fontana, California
Dr. Tjoa's primary practice is Fontana Medical Center, at 9961 Sierra Ave, Fontana, CA 92335 in San Bernardino County. The practice phone is (909) 427-5000.
- Fontana Medical Center9961 Sierra Ave, Fontana, CA 92335 · San Bernardino CountyPhone(909) 427-5000
Sources: Dmand AI Affiliation Data; and Doctors and Clinicians National Downloadable File (CMS)
Dr. Walter S. Tjoa is affiliated with 1 site of care and 1 medical group
Dr. Tjoa's primary practice is Fontana Medical Center in Fontana, California, part of Kaiser Permanente. The medical group on file is Southern California Permanente Medical Group.
Sources: Dmand AI Affiliation Data; Doctors and Clinicians National Downloadable File (CMS); and Dmand AI Org Hierarchy Data
Dmand AI tracks the EHR system at Dr. Walter S. Tjoa's practice
Dmand AI tracks the electronic health record (EHR) system at each site where Dr. Tjoa practices. Vendor and product names are available with a free account.
| Site | EHR vendor and product |
|---|---|
| Fontana Medical Center | Available with a free account |
Source: Dmand AI Technology Install Data
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Dr. Walter S. Tjoa is one of 1,910 dermatologists in California
Dermatology is Dr. Tjoa's primary specialty in the NPI Registry, under taxonomy code 207N00000X. Dr. Tjoa is board certified in dermatology by the American Board of Dermatology. Dmand AI has Dr. Tjoa's licenses on file in 4 states: California, Pennsylvania, New York and Florida.
Specialties and state licenses
- Dermatology, CaliforniaPrimary
- Pennsylvania license
- New York license
- Florida license
Dermatologists near Dr. Tjoa
Counts of dermatologists with a Dmand AI profile, by place and practice. Each opens the list.
1,910dermatologists in California
9dermatologists in Fontana
6dermatologists at Fontana Medical CenterSources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; and Dmand AI Peer Benchmarks
Dr. Walter S. Tjoa's patients have a median age of 62
Across all payers, Dmand AI patient panel data puts Dr. Tjoa's median patient age at 62, with 53% women.
Dr. Tjoa'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
- Women53%
- Men45%
Source: Dmand AI Patient Panel Data
Dr. Walter S. Tjoa wrote 84 Medicare Part D claims in 2022
In 2022, Dr. Tjoa wrote 84 Medicare Part D claims. Every claim was for a generic drug. They cover 4 drugs, with $2,068 in total drug cost. In 2021, CMS named 338 claims across 10 drugs.
Part D claims, 202284
Drugs named by CMS4
Total drug cost$2,068
Dr. Tjoa's most prescribed drugs by claims, 2022
CMS names a drug when it has 11 or more claims. Share is of the claims for drugs CMS names.
Part D claims for drugs CMS names, 2021 to 2022
- 2021
- 2022
- Claims for drugs CMS names
- 2021: 3382022: 8475%
Drugs named by CMS: 4 in 2022, 10 in 2021.
Source: Medicare Part D Prescribers - by Provider and Drug (CMS), 2024 data, released May 6, 2026
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Dr. Walter S. Tjoa has 2 publications on record
Dmand AI links 2 papers to Dr. Tjoa. The most frequent topics are Diarrhea, Escherichia coli Infections and Mexico. Dr. Tjoa's most frequent co-author is Herbert Lancashire Dupont, MD.
Papers2
Topics Dr. Tjoa writes about most
- Diarrhea
- Escherichia coli Infections
- Mexico
Dr. Tjoa's most frequent co-authors
Recent publications by Dr. Tjoa
BismuthDiarrheaEscherichia coli Infections
See who Dr. Tjoa researches with
Physician Network Discovery turns co-authorship, shared hospitals and shared groups into a map of who Dr. Tjoa works with, so you can find a warm path to the right dermatologists.
Sources: PubMed (National Library of Medicine); and Dmand AI Research Linkage
Dr. Walter S. Tjoa received $211 in industry payments from 2016 to 2024
CMS Open Payments shows 3 general payments to Dr. Tjoa from 3 drug and device companies from 2016 to 2024. Food and beverage make up the largest share, 100% of the total. Galderma Laboratories, L.P. paid the most, $141.
General payments to Dr. Tjoa by program year, 2016 to 2024
Companies that paid Dr. Tjoa the most, 2016 to 2024
Share is of all general payments to this clinician.
Source: Open Payments (CMS), 2025 data, released July 7, 2026
Dr. Walter S. Tjoa has 2 awards and honors on record
Dmand AI lists 2 awards for Dr. Tjoa, most recently CMS Stage 1 2012 in 2011.
Awards and honors for Dr. Tjoa
- 2011
- CMS Stage 1 2012
- Undated
- AAD Fellow
Source: Dmand AI Professional Profile Data
Dr. Walter S. Tjoa graduated from Catholic University of Leuven
Dr. Tjoa graduated from Catholic University of Leuven in 1978. Dr. Tjoa is a member of AAD.
- Medical school
- Board certified in dermatology
Source: Dmand AI Professional Profile Data
Dr. Walter S. Tjoa accepts plans from 1 insurance carrier
Dr. Tjoa is in network with 1 carrier, including Kaiser Permanente. EPO plans come from the most carriers, 1. Check the plan with the practice before a visit.
- Kaiser Permanente
Plan types Dr. Tjoa accepts, by number of carriers
- EPO1
- HMO1
- POS1
Source: Dmand AI Insurance Network Data
Sources for Dr. Walter S. Tjoa'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 DataDoctors and Clinicians National Downloadable File (CMS) (opens in a new tab) |
| Primary practice, affiliations and health system | Dmand AI Affiliation DataDoctors and Clinicians National Downloadable File (CMS) (opens in a new tab)Dmand AI Org Hierarchy Data |
| 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) |
| 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. Walter S. Tjoa
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. Walter S. Tjoa's NPI number?
Dr. Walter S. Tjoa's NPI number is 1801955463. It was assigned on December 8, 2006, and it is active in the NPI Registry.
What kind of doctor is Dr. Walter S. Tjoa?
Dr. Walter S. Tjoa is a dermatologist in Fontana, California. The primary specialty in the NPI Registry is Dermatology Physician (taxonomy code 207N00000X).
Where does Dr. Walter S. Tjoa practice?
Dr. Tjoa practices at 9961 Sierra Ave, Fontana, CA 92335. Dr. Tjoa's primary practice is Fontana Medical Center in Fontana, California, part of Kaiser Permanente.
What is Dr. Walter S. Tjoa's office phone number?
The practice phone on file for Dr. Tjoa is (909) 427-5000.
What is Dr. Walter S. Tjoa's medical license number?
Dr. Tjoa's California license number on file is C42142, one of the licenses on file in 4 states.
Which states has Dr. Walter S. Tjoa been licensed in?
Dmand AI has state licenses on file for Dr. Tjoa in California (1985 to 2025), Pennsylvania (1981 to 2014), New York (1983 to 1992) and Florida (1986 to 1987).
Which hospitals is Dr. Walter S. Tjoa affiliated with?
Dr. Tjoa practices at Fontana Medical Center in Fontana, California.
What medical group is Dr. Walter S. Tjoa part of?
Dr. Tjoa is linked to Southern California Permanente Medical Group.
Is Dr. Walter S. Tjoa board certified?
Yes. Dr. Tjoa is board certified in dermatology by the American Board of Dermatology.
Where did Dr. Walter S. Tjoa go to medical school?
Dr. Tjoa graduated from Catholic University of Leuven in 1978.
Show 6 more questionsShow fewer questions
What drugs does Dr. Walter S. Tjoa prescribe most?
In 2022 Medicare Part D data, Dr. Tjoa's most prescribed drugs by claims were Triamcinolone Acetonide, Fluocinonide and Hydrocortisone.
Has Dr. Walter S. Tjoa received payments from drug or device companies?
CMS Open Payments shows $211 in general payments to Dr. Tjoa from 3 companies from 2016 to 2024. The largest total came from Galderma Laboratories, L.P.
How long has Dr. Walter S. Tjoa been practicing?
Dr. Tjoa graduated from medical school in 1978, 48 years ago.
Does Dr. Walter S. Tjoa do research?
Dmand AI links 2 publications to Dr. Tjoa.
Who does Dr. Walter S. Tjoa publish with?
Dr. Tjoa's most frequent co-authors are Herbert Lancashire Dupont, MD (2 shared papers).
What insurance does Dr. Walter S. Tjoa accept?
Dr. Tjoa is in network with 1 carrier, including Kaiser Permanente. EPO plans come from the most carriers, 1. Check the plan with the practice before a visit.
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