Dr. Han Kyo K. Chang, MD
- Medicare services, 2017
- 766
- Part D claims, 2024
- 4,685
- Industry payments
- $571
- Affiliated sites
- 1
- Medical group
- 1
- Practice address
- 365 Tuolumne Street, Vallejo, CA 94590
- Practice phone
- Call (707) 784-8514
- Professional email
- Get professional email
- Personal email
- Get personal email
- Mobile number
- Get mobile number
Primary practice
Vallejo Family Health Services Center
FQHC - Main Site · Vallejo, California
Find Dr. Chang'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. Han Kyo K. Chang is an internist in Vallejo, California
Dr. Chang practices at Vallejo Family Health Services Center in Vallejo, California.
Dr. Chang's NPI, 1235127150, was assigned on October 13, 2005. Dr. Chang graduated from Seoul National University College of Medicine in 1966. Dr. Chang holds California license C138034.
- NPI
- 1235127150NPI Registry (opens in a new tab)
- NPI enumeration date
- October 13, 2005
- NPI status
- Active
- Practice phone
- (707) 784-8514
- Professional email
- Get email
- Personal email
- Get email
- Mobile number
- Get number
- Sex
- Male
- Medical school graduation
- 1966
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; and Dmand AI Affiliation Data
Dr. Han Kyo K. Chang practices at Vallejo Family Health Services Center in Vallejo, California
Dr. Chang's primary practice is Vallejo Family Health Services Center, at 365 Tuolumne Street, Vallejo, CA 94590 in Solano County. The practice phone is (707) 784-8514.
- Vallejo Family Health Services Center365 Tuolumne Street, Vallejo, CA 94590 · Solano CountyPhone(707) 784-8514
Source: Dmand AI Affiliation Data
Dr. Han Kyo K. Chang is affiliated with 1 site of care and 1 medical group
Dr. Chang's primary practice is Vallejo Family Health Services Center in Vallejo, California. The medical group on file is Solano County Health and Social Services. Dr. Chang's employer is on file too: a community health center (fqhc).
Sources: Dmand AI Affiliation Data; and Dmand AI Org Hierarchy Data
Dmand AI tracks the EHR system at Dr. Han Kyo K. Chang's practice
Dmand AI tracks the electronic health record (EHR) system at each site where Dr. Chang practices. Vendor and product names are available with a free account.
| Site | EHR vendor and product |
|---|---|
| Vallejo Family Health Services Center | Available with a free account |
Source: Dmand AI Technology Install Data
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Dr. Han Kyo K. Chang is one of 16,751 internists in California
Internal medicine is Dr. Chang's primary specialty in the NPI Registry, under taxonomy code 207R00000X. Dr. Chang is board certified in internal medicine by the American Board of Internal Medicine. Dmand AI has Dr. Chang's licenses on file in 2 states: California and New York.
Specialties and state licenses
- Internal medicine, CaliforniaPrimary
- Specialist, New York
Internists near Dr. Chang
Counts of internists 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. Han Kyo K. Chang billed Medicare for 766 services in 2017
CMS data shows 766 Medicare services from Dr. Chang across 6 procedure codes in 2017. Medicare paid $18,413 for them.
Dr. Chang's Medicare services by type, 2016 to 2017
- 2016
- 2017
- Office and hospital visits
- 2016: 1,0942017: 46158%
- Tests and treatments
- 2016: 7282017: 23068%
- Drugs given in the office
- 2016: 932017: 6332%
- Other services
- 2016: 1812017: 1293%
- Surgery
- 2016: 142017: 0100%
Where Dr. Chang's Medicare services took place, 2017
- In an office59678%
- In a facility17022%
Dr. Chang compared with the California median for internists, 2017
- Dr. Chang
- California median
- Medicare services
- 766vs 3612.1 times
- Part D claims
- 4,261vs 42110.1 times
Medians across 15,815 internists in California with Dmand AI profiles that report each measure.
Dr. Chang'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. Chang?
Medicare shows one payer. Book a meeting to get commercial claims data for Dr. Chang and other internists in California.
Sources: Medicare Physician & Other Practitioners - by Provider and Service (CMS), 2024 data; and Dmand AI Peer Benchmarks
Dr. Han Kyo K. Chang's patients have a median age of 63
Across all payers, Dmand AI patient panel data puts Dr. Chang's median patient age at 63, with 54% women.
Dr. Chang's patients across all payers
Dmand AI patient panel data covers Medicare, Medicaid and commercial patients.
Patient panel by age, all payers
Median age 63
Patient panel by sex, all payers
- Women54%
- Men45%
Source: Dmand AI Patient Panel Data
Dr. Han Kyo K. Chang wrote 4,685 Medicare Part D claims in 2024
In 2024, Dr. Chang wrote 4,685 Medicare Part D claims for 415 patients. 84% of them were for generic drugs. CMS names the drug for 4,261 of them, across 82 drugs with 11 or more claims each, at $382,913 in total drug cost. In 2023, CMS named 4,187 claims across 84 drugs.
Dr. Chang's Part D claims by kind of drug, 2024
- Generic3,927 claims84%
- Brand-name720 claims15%
- Other38 claims1%
Dr. Chang'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. Chang's Part D claims, 2024
- Antibiotics0%18 of 4,685 claims
- Antipsychotics, patients 65 and over1%25 of 4,685 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, 2023 to 2024
- 2023
- 2024
- Claims for drugs CMS names
- 2023: 4,1872024: 4,2612%
Drugs named by CMS: 82 in 2024, 84 in 2023.
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
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Dr. Han Kyo K. Chang received $571 in industry payments from 2016 to 2025
CMS Open Payments shows 35 general payments to Dr. Chang from 17 drug and device companies from 2016 to 2025. Food and beverage make up the largest share, 100% of the total. Amgen Inc. paid the most, $107.
General payments to Dr. Chang by program year, 2016 to 2025
Companies that paid Dr. Chang the most, 2016 to 2025
Share is of all general payments to this clinician.
Source: Open Payments (CMS), 2025 data, released July 7, 2026
Dr. Han Kyo K. Chang graduated from Seoul National University College of Medicine
Dr. Chang graduated from Seoul National University College of Medicine in 1966.
- Medical school
- Board certified in internal medicine
Source: Dmand AI Professional Profile Data
Dr. Han Kyo K. Chang accepts plans from 1 insurance carrier
Dr. Chang is in network with 1 carrier, including Elevance. HMO plans come from the most carriers, 1. Check the plan with the practice before a visit.
- Elevance
Plan types Dr. Chang accepts, by number of carriers
- HMO1
- Medicaid1
Source: Dmand AI Insurance Network Data
Sources for Dr. Han Kyo K. Chang'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 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) |
| 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. Han Kyo K. Chang
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. Han Kyo K. Chang's NPI number?
Dr. Han Kyo K. Chang's NPI number is 1235127150. It was assigned on October 13, 2005, and it is active in the NPI Registry.
What kind of doctor is Dr. Han Kyo K. Chang?
Dr. Han Kyo K. Chang is an internist in Vallejo, California. The primary specialty in the NPI Registry is Internal Medicine Physician (taxonomy code 207R00000X).
Where does Dr. Han Kyo K. Chang practice?
Dr. Chang practices at 365 Tuolumne Street, Vallejo, CA 94590. Dr. Chang's primary practice is Vallejo Family Health Services Center in Vallejo, California.
What is Dr. Han Kyo K. Chang's office phone number?
The practice phone on file for Dr. Chang is (707) 784-8514.
What is Dr. Han Kyo K. Chang's medical license number?
Dr. Chang holds California license C138034, one of the licenses on file in 2 states.
Which states has Dr. Han Kyo K. Chang been licensed in?
Dmand AI has state licenses on file for Dr. Chang in California (2015 to 2027) and New York (1975 to 2017).
What medical group is Dr. Han Kyo K. Chang part of?
Dr. Chang is linked to Solano County Health and Social Services.
Does Dr. Han Kyo K. Chang accept Medicare?
Yes. CMS data shows Dr. Chang billed Medicare for 766 services in 2017.
Is Dr. Han Kyo K. Chang board certified?
Yes. Dr. Chang is board certified in internal medicine by the American Board of Internal Medicine.
What services does Dr. Han Kyo K. Chang bill to Medicare?
In 2017, Dr. Chang's most billed Medicare services were office visit, established patient (99213), heart test or procedure (93010) and medical service (99334).
Show 5 more questionsShow fewer questions
Where did Dr. Han Kyo K. Chang go to medical school?
Dr. Chang graduated from Seoul National University College of Medicine in 1966.
What drugs does Dr. Han Kyo K. Chang prescribe most?
In 2024 Medicare Part D data, Dr. Chang's most prescribed drugs by claims were Atorvastatin Calcium, Amlodipine Besylate and Losartan Potassium.
Has Dr. Han Kyo K. Chang received payments from drug or device companies?
CMS Open Payments shows $571 in general payments to Dr. Chang from 17 companies from 2016 to 2025. The largest total came from Amgen Inc.
How long has Dr. Han Kyo K. Chang been practicing?
Dr. Chang graduated from medical school in 1966, 60 years ago.
What insurance does Dr. Han Kyo K. Chang accept?
Dr. Chang is in network with 1 carrier, including Elevance. HMO plans come from the most carriers, 1. Check the plan with the practice before a visit.
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