Dr. Grace Gyungah Ahn, MD
- Medicare services, 2023
- 15
- Medicare patients, 2024
- 16
- Part D claims, 2024
- 201
- Hospital affiliations
- 2
- Industry payments
- $174
- Practice address
- 1425 S Main Street, Walnut Creek, CA 94596
- Practice phone
- Call (925) 295-4000
- Professional email
- Get professional email
- Personal email
- Get personal email
- Mobile number
- Get mobile number
Primary practice
Find Dr. Ahn'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. Grace Gyungah Ahn is an emergency medicine physician in Walnut Creek, California
Dr. Ahn practices at Walnut Creek Medical Center in Walnut Creek, California, part of Kaiser Permanente.
Dr. Ahn's NPI, 1194923813, was assigned on July 3, 2007. Dr. Ahn graduated from University Of Michigan Medical School in 2006. Dr. Ahn holds California license A100922.
- NPI
- 1194923813NPI Registry (opens in a new tab)
- Medicare PAC ID
- 6305999384
- NPI enumeration date
- July 3, 2007
- NPI status
- Active
- Accepts Medicare assignment
- Yes
- Practice phone
- (925) 295-4000
- Professional email
- Get email
- Personal email
- Get email
- Mobile number
- Get number
- Sex
- Female
- Estimated age
- 46
- Medical school graduation
- 2006
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; Dmand AI Affiliation Data; and Doctors and Clinicians National Downloadable File (CMS)
Dr. Grace Gyungah Ahn practices at Walnut Creek Medical Center in Walnut Creek, California
Dr. Ahn's primary practice is Walnut Creek Medical Center, at 1425 S Main Street, Walnut Creek, CA 94596 in Contra Costa County. The practice phone is (925) 295-4000.
- Walnut Creek Medical Center1425 S Main Street, Walnut Creek, CA 94596 · Contra Costa CountyPhone(925) 295-4000
Source: Dmand AI Affiliation Data
Dr. Grace Gyungah Ahn is affiliated with 2 sites of care and 1 medical group
Dr. Ahn's primary practice is Walnut Creek Medical Center in Walnut Creek, California, part of Kaiser Permanente. Dr. Ahn is also affiliated with Zuckerberg San Francisco General Hospital and Trauma Center. The medical group on file is The Permanente Medical Group, Inc.
Sources: Dmand AI Affiliation Data; and Dmand AI Org Hierarchy Data
Dmand AI tracks the EHR system at Dr. Grace Gyungah Ahn's practice
Dmand AI tracks the electronic health record (EHR) system at each site where Dr. Ahn practices, 2 sites in all. Vendor and product names are available with a free account.
| Site | EHR vendor and product |
|---|---|
| Walnut Creek Medical Center | Available with a free account |
| +1 more affiliated site | Available with a free account |
Source: Dmand AI Technology Install Data
For health IT teams
Dmand AI maps EHR vendors, IT decision makers and buying committees across Kaiser Permanente and 6.2K+ hospitals, with verified contacts in the same login.
Dr. Grace Gyungah Ahn is one of 7,423 emergency medicine physicians in California
Emergency medicine is Dr. Ahn's primary specialty in the NPI Registry, under taxonomy code 207P00000X. Dr. Ahn is board certified in emergency medicine by the American Board of Emergency Medicine. Dr. Ahn is licensed in California.
Specialties and state licenses
- Emergency medicine, CaliforniaPrimary
Emergency medicine physicians near Dr. Ahn
Counts of emergency medicine physicians 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. Grace Gyungah Ahn billed Medicare for 15 services in 2023
CMS data shows 15 Medicare services from Dr. Ahn across 1 procedure code in 2023, for 16 Medicare patients. Medicare paid $1,245 for them. Every service was in a facility, such as a hospital, rather than an office.
Dr. Ahn's Medicare services by type, 2022 to 2023
- 2022
- 2023
- Office and hospital visits
- 2022: 122023: 1525%
Dr. Ahn compared with the California median for emergency medicine physicians, 2023
- Dr. Ahn
- California median
- Medicare services
- 15vs 26594% below
- Medicare patients
- 16vs 24393% below
- Part D claims
- 57vs 628% below
Medians across 7,079 emergency medicine physicians in California with Dmand AI profiles that report each measure.
Dr. Ahn's most billed Medicare procedure codes, 2023
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. Ahn?
Medicare shows one payer. Book a meeting to get commercial claims data for Dr. Ahn and other emergency medicine physicians in California.
Sources: Medicare Physician & Other Practitioners - by Provider and Service (CMS), 2024 data; and Dmand AI Peer Benchmarks
Dr. Grace Gyungah Ahn treated 16 Medicare patients in 2024, average age 67
CMS counts 16 Medicare patients who saw Dr. Ahn in 2024. The largest group is 85 and over, with 0 patients. Their average risk score is 1.70, 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. Ahn's median patient age at 35, with 57% women.
Dr. Ahn's Medicare patients by age, 2024
CMS leaves out age groups with fewer than 11 patients.
Dr. Ahn's patients across all payers
Dmand AI patient panel data covers Medicare, Medicaid and commercial patients.
Patient panel by age, all payers
Median age 35
Patient panel by sex, all payers
- Women57%
- Men42%
Sources: Dmand AI Patient Panel Data; and Medicare Physician & Other Practitioners - by Provider (CMS), 2024 data
Dr. Grace Gyungah Ahn wrote 201 Medicare Part D claims in 2024
In 2024, Dr. Ahn wrote 201 Medicare Part D claims for 133 patients. 90% of them were for generic drugs. CMS names the drug for 57 of them, across 3 drugs with 11 or more claims each, at $450 in total drug cost. In 2023, CMS named 26 claims across 2 drugs.
Dr. Ahn's Part D claims by kind of drug, 2024
- Generic180 claims90%
- Brand-name21 claims10%
Dr. Ahn'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. Ahn's Part D claims, 2024
- Opioids9%18 of 201 claims
- Antibiotics40%81 of 201 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: 262024: 57119%
Drugs named by CMS: 3 in 2024, 2 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. Grace Gyungah Ahn takes part in Medicare
Dr. Ahn 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)
For MedTech and pharma teams
Filter 7.4M+ HCPs by Medicare procedures, Part D drugs and Open Payments history, then reach them with verified contacts in one login.
Dr. Grace Gyungah Ahn received $174 in industry payments from 2023 to 2025
CMS Open Payments shows 3 general payments to Dr. Ahn from 3 drug and device companies from 2023 to 2025. Food and beverage make up the largest share, 100% of the total. Boehringer Ingelheim Pharmaceuticals, Inc. paid the most, $113.
General payments to Dr. Ahn by program year, 2023 to 2025
Companies that paid Dr. Ahn the most, 2023 to 2025
Share is of all general payments to this clinician.
Source: Open Payments (CMS), 2025 data, released July 7, 2026
Dr. Grace Gyungah Ahn graduated from University Of Michigan Medical School
Dr. Ahn graduated from University Of Michigan Medical School in 2006.
- Medical school
- Board certified in emergency medicine
Source: Dmand AI Professional Profile Data
Dr. Grace Gyungah Ahn accepts plans from 2 insurance carriers
Dr. Ahn is in network with 2 carriers, including CMS Medicare and Kaiser Permanente. EPO plans come from the most carriers, 1. Check the plan with the practice before a visit.
- CMS Medicare
- Kaiser Permanente
Plan types Dr. Ahn accepts, by number of carriers
- EPO1
- Medicare1
Source: Dmand AI Insurance Network Data
Sources for Dr. Grace Gyungah Ahn'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) |
| 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) |
| 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. Grace Gyungah Ahn
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. Grace Gyungah Ahn's NPI number?
Dr. Grace Gyungah Ahn's NPI number is 1194923813. It was assigned on July 3, 2007, and it is active in the NPI Registry.
What kind of doctor is Dr. Grace Gyungah Ahn?
Dr. Grace Gyungah Ahn is an emergency medicine physician in Walnut Creek, California. The primary specialty in the NPI Registry is Emergency Medicine Physician (taxonomy code 207P00000X).
Where does Dr. Grace Gyungah Ahn practice?
Dr. Ahn practices at 1425 S Main Street, Walnut Creek, CA 94596. Dr. Ahn's primary practice is Walnut Creek Medical Center in Walnut Creek, California, part of Kaiser Permanente.
What is Dr. Grace Gyungah Ahn's office phone number?
The practice phone on file for Dr. Ahn is (925) 295-4000.
What is Dr. Grace Gyungah Ahn's medical license number?
Dr. Ahn holds California license A100922.
Which hospitals is Dr. Grace Gyungah Ahn affiliated with?
Dr. Ahn practices at Walnut Creek Medical Center in Walnut Creek, California. Dr. Ahn is also affiliated with Zuckerberg San Francisco General Hospital and Trauma Center.
What medical group is Dr. Grace Gyungah Ahn part of?
Dr. Ahn is linked to The Permanente Medical Group, Inc.
Does Dr. Grace Gyungah Ahn accept Medicare?
Yes. CMS data shows Dr. Ahn billed Medicare for 15 services in 2023, and Dr. Ahn accepts Medicare assignment.
How many Medicare patients does Dr. Grace Gyungah Ahn see?
CMS counts 16 Medicare patients who saw Dr. Ahn in 2024, with an average age of 67.
Is Dr. Grace Gyungah Ahn board certified?
Yes. Dr. Ahn is board certified in emergency medicine by the American Board of Emergency Medicine.
Show 6 more questionsShow fewer questions
What services does Dr. Grace Gyungah Ahn bill to Medicare?
In 2023, Dr. Ahn's most billed Medicare services were emergency department visit (99284).
Where did Dr. Grace Gyungah Ahn go to medical school?
Dr. Ahn graduated from University Of Michigan Medical School in 2006.
What drugs does Dr. Grace Gyungah Ahn prescribe most?
In 2024 Medicare Part D data, Dr. Ahn's most prescribed drugs by claims were Ondansetron ODT, Amoxicillin-Clavulanate Potass and Ciprofloxacin HCl.
Has Dr. Grace Gyungah Ahn received payments from drug or device companies?
CMS Open Payments shows $174 in general payments to Dr. Ahn from 3 companies from 2023 to 2025. The largest total came from Boehringer Ingelheim Pharmaceuticals, Inc.
How long has Dr. Grace Gyungah Ahn been practicing?
Dr. Ahn graduated from medical school in 2006, 20 years ago.
What insurance does Dr. Grace Gyungah Ahn accept?
Dr. Ahn is in network with 2 carriers, including CMS Medicare and Kaiser Permanente. EPO plans come from the most carriers, 1. Check the plan with the practice before a visit.
Selling to emergency medicine practices?
See emergency medicine physicians in California by site of care and group
Find the practices, groups and hospitals they work with, and the right people to contact at each.
- 30 days free
- Self-serve
- No credit card