Dr. Gemma Tok Hyon Ko, MD
- Medicare services, 2024
- 764
- Medicare patients, 2024
- 52
- Part D claims, 2024
- 3,591
- Hospital affiliations
- 1
- Industry payments
- $2,473
- Practice address
- 4511 Rosemead Blvd, Pico Rivera, CA 90660
- Practice phone
- Call (562) 692-3388
- Professional email
- Get professional email
- Personal email
- Get personal email
- Mobile number
- Get mobile number
Primary practice
Gemma Th Ko,MD. Inc.
Pico Rivera, California
Find Dr. Ko'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. Gemma Tok Hyon Ko is an internist in Pico Rivera, California
Dr. Ko practices at Gemma Th Ko,MD. Inc. in Pico Rivera, California.
Dr. Ko's NPI, 1437167715, was assigned on August 3, 2006. Dr. Ko graduated from John A. Burns School of Medicine in 1987. Dr. Ko holds California license G70866.
- NPI
- 1437167715NPI Registry (opens in a new tab)
- Medicare PAC ID
- 2163428475
- NPI enumeration date
- August 3, 2006
- NPI status
- Active
- Accepts Medicare assignment
- Yes
- Practice phone
- (562) 692-3388
- Professional email
- Get email
- Personal email
- Get email
- Mobile number
- Get number
- Sex
- Female
- Estimated age
- 62
- Medical school graduation
- 1987
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; Dmand AI Practice Data; and Doctors and Clinicians National Downloadable File (CMS)
Dr. Gemma Tok Hyon Ko practices at Gemma Th Ko,MD. Inc. in Pico Rivera, California
Dr. Ko's primary practice is Gemma Th Ko,MD. Inc., at 4511 Rosemead Blvd, Pico Rivera, CA 90660 in Los Angeles County. The practice phone is (562) 692-3388.
- Gemma Th Ko,MD. Inc.4511 Rosemead Blvd, Pico Rivera, CA 90660 · Los Angeles CountyPhone(562) 692-3388
Sources: NPPES NPI Registry (CMS); and Dmand AI Practice Data
Dr. Gemma Tok Hyon Ko is affiliated with 3 sites of care and 1 medical group
Dr. Ko's primary practice is Gemma Th Ko,MD. Inc. in Pico Rivera, California. Dr. Ko is also affiliated with PIH Health Whittier Hospital. The medical group on file is Foundation Medical Group. Dmand AI also links Dr. Ko 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. Gemma Tok Hyon Ko's practice
Dmand AI tracks the electronic health record (EHR) system at each site where Dr. Ko practices, 2 sites in all. Vendor and product names are available with a free account.
| Site | EHR vendor and product |
|---|---|
| Gemma Th Ko,MD. Inc. | Available with a free account |
| +2 more affiliated sites | Available with a free account |
Source: Dmand AI Technology Install Data
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Dr. Gemma Tok Hyon Ko is one of 16,751 internists in California
Internal medicine is Dr. Ko's primary specialty in the NPI Registry, under taxonomy code 207R00000X. Dr. Ko is board certified in internal medicine by the National Board of Physicians and Surgeons. Dmand AI has Dr. Ko's licenses on file in 2 states: California and Hawaii.
Specialties and state licenses
- Internal medicine, CaliforniaPrimary
- Hawaii license
Clinical focus
Dmand AI lists anxiety, arthritis, asthma, cardiomyopathy, chronic anemia, chronic diabetes, chronic hypertension and chronic obstructive pulmonary disease (COPD) among the conditions Dr. Ko treats.
Internists near Dr. Ko
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. Gemma Tok Hyon Ko billed Medicare for 764 services in 2024
CMS data shows 764 Medicare services from Dr. Ko across 10 procedure codes in 2024, for 52 Medicare patients. Medicare paid $44,748 for them. Every service was in an office.
Dr. Ko's Medicare services by type, 2023 to 2024
- 2023
- 2024
- Office and hospital visits
- 2023: 3022024: 51671%
- Other services
- 2023: 492024: 135176%
- Surgery
- 2023: 842024: 11335%
- Tests and treatments
- 2023: 222024: 0100%
Dr. Ko compared with the California median for internists, 2024
- Dr. Ko
- California median
- Medicare services
- 764vs 3612.1 times
- Medicare patients
- 52vs 15166% below
- Part D claims
- 3,079vs 4217.3 times
Medians across 15,815 internists in California with Dmand AI profiles that report each measure.
Dr. Ko'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. Ko?
Medicare shows one payer. Book a meeting to get commercial claims data for Dr. Ko and other internists in California.
Sources: Medicare Physician & Other Practitioners - by Provider and Service (CMS), 2024 data; and Dmand AI Peer Benchmarks
Dr. Gemma Tok Hyon Ko treated 52 Medicare patients in 2024, average age 77
CMS counts 52 Medicare patients who saw Dr. Ko in 2024. The largest group is 75 to 84, with 17 patients. 75% of them have high blood pressure, and 75% have high cholesterol. 52% are also on Medicaid. Their average risk score is 1.60, 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. Ko's median patient age at 60, with 65% women.
Dr. Ko's Medicare patients by age, 2024
CMS leaves out age groups with fewer than 11 patients.
Dr. Ko's Medicare patients by sex, 2024
- Women3771%
- Men1529%
Chronic conditions among Dr. Ko's Medicare patients, 2024
- High blood pressure75%
- High cholesterol75%
- Diabetes48%
- Arthritis42%
- Chronic kidney disease38%
- Depression37%
- Mood disorders37%
- Anxiety33%
Share of Medicare patients with each condition. A patient can have several.
Dr. Ko's patients across all payers
Dmand AI patient panel data covers Medicare, Medicaid and commercial patients.
Patient panel by age, all payers
Median age 60
Patient panel by sex, all payers
- Women65%
- Men35%
Sources: Dmand AI Patient Panel Data; and Medicare Physician & Other Practitioners - by Provider (CMS), 2024 data
Dr. Gemma Tok Hyon Ko wrote 3,591 Medicare Part D claims in 2024
In 2024, Dr. Ko wrote 3,591 Medicare Part D claims for 145 patients. 89% of them were for generic drugs. CMS names the drug for 3,079 of them, across 89 drugs with 11 or more claims each, at $246,347 in total drug cost. In 2023, CMS named 2,997 claims across 84 drugs.
Dr. Ko's Part D claims by kind of drug, 2024
- Generic3,196 claims89%
- Brand-name371 claims10%
- Other24 claims1%
Dr. Ko'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. Ko's Part D claims, 2024
- Opioids4%154 of 3,591 claims
- Antibiotics2%77 of 3,591 claims
- Antipsychotics, patients 65 and over2%62 of 3,591 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: 2,9972024: 3,0793%
Drugs named by CMS: 89 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
How Dr. Gemma Tok Hyon Ko takes part in Medicare
Dr. Ko 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. Gemma Tok Hyon Ko received $2,473 in industry payments from 2016 to 2025
CMS Open Payments shows 134 general payments to Dr. Ko from 18 drug and device companies from 2016 to 2025. Food and beverage make up the largest share, 99% of the total. Novo Nordisk Inc paid the most, $543.
General payments to Dr. Ko by program year, 2016 to 2025
General payments to Dr. Ko by kind, 2016 to 2025
- Food and beverage$2,45399%
- Education$201%
Companies that paid Dr. Ko 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. Gemma Tok Hyon Ko has 1 award and honors on record
Dmand AI lists 1 award for Dr. Ko, most recently CMS Stage 1 2012 in 2012.
Awards and honors for Dr. Ko
- 2012
- CMS Stage 1 2012
Source: Dmand AI Professional Profile Data
Dr. Gemma Tok Hyon Ko graduated from John A. Burns School of Medicine
Dr. Ko graduated from John A. Burns School of Medicine in 1987.
- Medical school
- Board certified in internal medicine
Source: Dmand AI Professional Profile Data
Dr. Gemma Tok Hyon Ko accepts plans from 17 insurance carriers
Dr. Ko is in network with 17 carriers, including Aetna, Blue Cross Blue Shield of Michigan and United Healthcare. Medicare plans come from the most carriers, 10. Check the plan with the practice before a visit.
- Aetna
- Blue Cross Blue Shield of Michigan
- United Healthcare
- Elevance
- HCSC
- Humana
- LA Care
- Blue Cross Blue Shield of Massachusetts
- +9 more carriersWith a free account
Plan types Dr. Ko accepts, by number of carriers
- Medicare10
- PPO10
- HMO9
- EPO4
- POS4
- Medicaid1
Source: Dmand AI Insurance Network Data
Sources for Dr. Gemma Tok Hyon Ko'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 DataMedicare Physician & Other Practitioners - by Provider (CMS) (opens in a new tab) |
| 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) |
| 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. Gemma Tok Hyon Ko
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. Gemma Tok Hyon Ko's NPI number?
Dr. Gemma Tok Hyon Ko's NPI number is 1437167715. It was assigned on August 3, 2006, and it is active in the NPI Registry.
What kind of doctor is Dr. Gemma Tok Hyon Ko?
Dr. Gemma Tok Hyon Ko is an internist in Pico Rivera, California. The primary specialty in the NPI Registry is Internal Medicine Physician (taxonomy code 207R00000X).
Where does Dr. Gemma Tok Hyon Ko practice?
Dr. Ko practices at 4511 Rosemead Blvd, Pico Rivera, CA 90660. Dr. Ko's primary practice is Gemma Th Ko,MD. Inc. in Pico Rivera, California. Dmand AI also links Dr. Ko to 1 group practice or clinic.
What is Dr. Gemma Tok Hyon Ko's office phone number?
The practice phone on file for Dr. Ko is (562) 692-3388.
What is Dr. Gemma Tok Hyon Ko's medical license number?
Dr. Ko holds California license G70866, one of the licenses on file in 2 states.
Which states has Dr. Gemma Tok Hyon Ko been licensed in?
Dmand AI has state licenses on file for Dr. Ko in California (1991 to 2027) and Hawaii (1987 to 1994).
Which hospitals is Dr. Gemma Tok Hyon Ko affiliated with?
Dr. Ko is affiliated with PIH Health Whittier Hospital.
What medical group is Dr. Gemma Tok Hyon Ko part of?
Dr. Ko is linked to Foundation Medical Group.
Does Dr. Gemma Tok Hyon Ko accept Medicare?
Yes. CMS data shows Dr. Ko billed Medicare for 764 services in 2024, and Dr. Ko accepts Medicare assignment.
How many Medicare patients does Dr. Gemma Tok Hyon Ko see?
CMS counts 52 Medicare patients who saw Dr. Ko in 2024, with an average age of 77.
Show 7 more questionsShow fewer questions
Is Dr. Gemma Tok Hyon Ko board certified?
Yes. Dr. Ko is board certified in internal medicine by the National Board of Physicians and Surgeons.
What services does Dr. Gemma Tok Hyon Ko bill to Medicare?
In 2024, Dr. Ko's most billed Medicare services were office visit, established patient (99214), surgery: heart and blood vessels (36415) and medicare service (G2211).
Where did Dr. Gemma Tok Hyon Ko go to medical school?
Dr. Ko graduated from John A. Burns School of Medicine in 1987.
What drugs does Dr. Gemma Tok Hyon Ko prescribe most?
In 2024 Medicare Part D data, Dr. Ko's most prescribed drugs by claims were Atorvastatin Calcium, Losartan Potassium and Hydrocodone-Acetaminophen.
Has Dr. Gemma Tok Hyon Ko received payments from drug or device companies?
CMS Open Payments shows $2,473 in general payments to Dr. Ko from 18 companies from 2016 to 2025. The largest total came from Novo Nordisk Inc.
How long has Dr. Gemma Tok Hyon Ko been practicing?
Dr. Ko graduated from medical school in 1987, 39 years ago.
What insurance does Dr. Gemma Tok Hyon Ko accept?
Dr. Ko is in network with 17 carriers, including Aetna, Blue Cross Blue Shield of Michigan and United Healthcare. Medicare plans come from the most carriers, 10. Check the plan with the practice before a visit.
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