Dr. Charissa Hoi Yan So, MD
- Medicare services, 2019
- 32
- Part D claims, 2024
- 123
- Hospital affiliations
- 1
- Medical group
- 1
- Insurance carriers
- 1
- Practice address
- 14445 Olive View Drive, Sylmar, CA 91342
- Practice phone
- Call (818) 364-1555
- Professional email
- Get professional email
- Personal email
- Get personal email
- Mobile number
- Get mobile number
Primary practice
Find Dr. So's professional email, personal email and mobile number
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Dr. Charissa Hoi Yan So is an internist in Sylmar, California
Dr. So practices at Olive View-UCLA Medical Center in Sylmar, California, part of County of Los Angeles.
Dr. So's NPI, 1558563700, was assigned on June 1, 2007. Dr. So graduated from UC Irvine School of Medicine in 2005. Dr. So holds California license A97824.
- NPI
- 1558563700NPI Registry (opens in a new tab)
- Medicare PAC ID
- 9537227921
- NPI enumeration date
- June 1, 2007
- NPI status
- Active
- Accepts Medicare assignment
- Yes
- Practice phone
- (818) 364-1555
- Professional email
- Get email
- Personal email
- Get email
- Mobile number
- Get number
- Sex
- Female
- Estimated age
- 47
- Medical school graduation
- 2005
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; Dmand AI Affiliation Data; and Doctors and Clinicians National Downloadable File (CMS)
Dr. Charissa Hoi Yan So practices at Olive View-UCLA Medical Center in Sylmar, California
Dr. So's primary practice is Olive View-UCLA Medical Center, at 14445 Olive View Drive, Sylmar, CA 91342 in Los Angeles County. The practice phone is (818) 364-1555.
- Olive View-UCLA Medical Center14445 Olive View Drive, Sylmar, CA 91342 · Los Angeles CountyPhone(818) 364-1555
Source: Dmand AI Affiliation Data
Dr. Charissa Hoi Yan So is affiliated with 1 site of care and 1 medical group
Dr. So's primary practice is Olive View-UCLA Medical Center in Sylmar, California, part of County of Los Angeles. The medical group on file is Harbor-UCLA Medical Center. Dr. So's employer is on file too: a hospital.
Sources: Dmand AI Affiliation Data; and Dmand AI Org Hierarchy Data
Dmand AI tracks the EHR system at Dr. Charissa Hoi Yan So's practice
Dmand AI tracks the electronic health record (EHR) system at each site where Dr. So practices. Vendor and product names are available with a free account.
| Site | EHR vendor and product |
|---|---|
| Olive View-UCLA Medical Center | Available with a free account |
Source: Dmand AI Technology Install Data
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Dr. Charissa Hoi Yan So is one of 16,751 internists in California
Internal medicine is Dr. So's primary specialty in the NPI Registry, under taxonomy code 207R00000X. Dr. So is board certified in internal medicine by the American Board of Internal Medicine. Dr. So is licensed in California.
Specialties and state licenses
- Internal medicine, CaliforniaPrimary
Clinical focus
Dmand AI lists asthma and plantar fasciitis among the conditions Dr. So treats.
Internists near Dr. So
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. Charissa Hoi Yan So billed Medicare for 32 services in 2019
CMS data shows 32 Medicare services from Dr. So across 2 procedure codes in 2019. Medicare paid $337 for them. Every service was in a facility, such as a hospital, rather than an office.
Dr. So's Medicare services by type, 2017 to 2019
- 2017
- 2019
- Office and hospital visits
- 2017: 122019: 2175%
- Surgery
- 2017: 02019: 11
Dr. So compared with the California median for internists, 2019
- Dr. So
- California median
- Medicare services
- 32vs 36191% below
- Part D claims
- 13vs 42197% below
Medians across 15,815 internists in California with Dmand AI profiles that report each measure.
Dr. So's most billed Medicare procedure codes, 2019
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. So?
Medicare shows one payer. Book a meeting to get commercial claims data for Dr. So and other internists in California.
Sources: Medicare Physician & Other Practitioners - by Provider and Service (CMS), 2024 data; and Dmand AI Peer Benchmarks
Dr. Charissa Hoi Yan So's patients have a median age of 60
Across all payers, Dmand AI patient panel data puts Dr. So's median patient age at 60, with 58% women.
Dr. So'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
- Women58%
- Men42%
Source: Dmand AI Patient Panel Data
Dr. Charissa Hoi Yan So wrote 123 Medicare Part D claims in 2024
In 2024, Dr. So wrote 123 Medicare Part D claims for 61 patients. 89% of them were for generic drugs. CMS names the drug for 13 of them, across 1 drug with 11 or more claims each, at $36 in total drug cost. In 2023, CMS named 24 claims across 1 drug.
Dr. So's Part D claims by kind of drug, 2024
- Generic110 claims89%
- Brand-name13 claims11%
Dr. So'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. So's Part D claims, 2024
- Antibiotics17%21 of 123 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: 242024: 1346%
Drugs named by CMS: 1 in 2024, 1 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. Charissa Hoi Yan So takes part in Medicare
Dr. So 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. Charissa Hoi Yan So graduated from UC Irvine School of Medicine
Dr. So graduated from UC Irvine School of Medicine in 2005.
- Medical school
- Board certified in internal medicine
Source: Dmand AI Professional Profile Data
Dr. Charissa Hoi Yan So accepts plans from 1 insurance carrier
Dr. So is in network with 1 carrier, including CMS Medicare. Medicare plans come from the most carriers, 1. Check the plan with the practice before a visit.
- CMS Medicare
Source: Dmand AI Insurance Network Data
Sources for Dr. Charissa Hoi Yan So'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) |
| MIPS scores, telehealth, assignment and procedure percentiles | Doctors and Clinicians National Downloadable File (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. Charissa Hoi Yan So
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. Charissa Hoi Yan So's NPI number?
Dr. Charissa Hoi Yan So's NPI number is 1558563700. It was assigned on June 1, 2007, and it is active in the NPI Registry.
What kind of doctor is Dr. Charissa Hoi Yan So?
Dr. Charissa Hoi Yan So is an internist in Sylmar, California. The primary specialty in the NPI Registry is Internal Medicine Physician (taxonomy code 207R00000X).
Where does Dr. Charissa Hoi Yan So practice?
Dr. So practices at 14445 Olive View Drive, Sylmar, CA 91342. Dr. So's primary practice is Olive View-UCLA Medical Center in Sylmar, California, part of County of Los Angeles.
What is Dr. Charissa Hoi Yan So's office phone number?
The practice phone on file for Dr. So is (818) 364-1555.
What is Dr. Charissa Hoi Yan So's medical license number?
Dr. So holds California license A97824.
Which hospitals is Dr. Charissa Hoi Yan So affiliated with?
Dr. So practices at Olive View-UCLA Medical Center in Sylmar, California.
What medical group is Dr. Charissa Hoi Yan So part of?
Dr. So is linked to Harbor-UCLA Medical Center.
Does Dr. Charissa Hoi Yan So accept Medicare?
Yes. CMS data shows Dr. So billed Medicare for 32 services in 2019, and Dr. So accepts Medicare assignment.
Is Dr. Charissa Hoi Yan So board certified?
Yes. Dr. So is board certified in internal medicine by the American Board of Internal Medicine.
What services does Dr. Charissa Hoi Yan So bill to Medicare?
In 2019, Dr. So's most billed Medicare services were office visit, established patient (99212) and surgery: heart and blood vessels (36415).
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Where did Dr. Charissa Hoi Yan So go to medical school?
Dr. So graduated from UC Irvine School of Medicine in 2005.
What drugs does Dr. Charissa Hoi Yan So prescribe most?
In 2024 Medicare Part D data, Dr. So's most prescribed drugs by claims were Ibuprofen.
How long has Dr. Charissa Hoi Yan So been practicing?
Dr. So graduated from medical school in 2005, 21 years ago.
What insurance does Dr. Charissa Hoi Yan So accept?
Dr. So is in network with 1 carrier, including CMS Medicare. Medicare plans come from the most carriers, 1. Check the plan with the practice before a visit.
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