Darwin C. Tsang, OD
- Medicare patients, 2024
- 170
- Part D claims, 2024
- 17
- Industry payments
- $73
- Affiliated sites
- 1
- Medical group
- 1
- Practice address
- 1001 Grand Ave, San Rafael, CA 94901
- Practice phone
- Call (415) 453-3812
- Professional email
- Get professional email
- Personal email
- Get personal email
- Mobile number
- Get mobile number
Primary practice
Marin Optometric Group, Inc
San Rafael, California
Find Darwin Tsang'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.
Darwin C. Tsang is an optometrist in San Rafael, California
Darwin Tsang practices at Marin Optometric Group, Inc in San Rafael, California.
Darwin Tsang's NPI, 1619344918, was assigned on August 21, 2015. Darwin Tsang graduated from New England College of Optometry in 2015. Darwin Tsang holds California license 15225 TLG.
- NPI
- 1619344918NPI Registry (opens in a new tab)
- Medicare PAC ID
- 9931401429
- NPI enumeration date
- August 21, 2015
- NPI status
- Active
- Accepts Medicare assignment
- Yes
- Practice phone
- (415) 453-3812
- Professional email
- Get email
- Personal email
- Get email
- Mobile number
- Get number
- Sex
- Male
- Estimated age
- 37
- Medical school graduation
- 2015
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; Dmand AI Practice Data; and Doctors and Clinicians National Downloadable File (CMS)
Darwin C. Tsang practices at Marin Optometric Group, Inc in San Rafael, California
Darwin Tsang's primary practice is Marin Optometric Group, Inc, at 1001 Grand Ave, San Rafael, CA 94901 in Marin County. The practice phone is (415) 453-3812.
- Marin Optometric Group, Inc1001 Grand Ave, San Rafael, CA 94901 · Marin CountyPhone(415) 453-3812
Sources: NPPES NPI Registry (CMS); and Dmand AI Practice Data
Darwin C. Tsang is affiliated with 2 sites of care and 1 medical group
Darwin Tsang's primary practice is Marin Optometric Group, Inc in San Rafael, California. Dmand AI also links Darwin Tsang to 1 group practice or clinic and 1 medical group, each 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 Darwin C. Tsang's practice
Dmand AI tracks the electronic health record (EHR) system at each site where Darwin Tsang practices. Vendor and product names are available with a free account.
| Site | EHR vendor and product |
|---|---|
| Marin Optometric Group, Inc | Available with a free account |
| +1 more site and 1 medical group | Available with a free account |
Source: Dmand AI Technology Install Data
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Darwin C. Tsang is one of 7,206 optometrists in California
Optometrist is Darwin Tsang's primary specialty in the NPI Registry, under taxonomy code 152W00000X. Darwin Tsang is licensed in California.
Specialties and state licenses
- Optometrist, CaliforniaPrimary
Optometrists near Darwin Tsang
Counts of optometrists 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
Darwin C. Tsang treated 170 Medicare patients in 2024, average age 76
CMS counts 170 Medicare patients who saw Darwin Tsang in 2024. The largest group is 65 to 74, with 75 patients. 75% of them have high cholesterol, and 57% have high blood pressure. Their average risk score is 1.05, where 1.00 is the Medicare average.
Across all payers, Dmand AI patient panel data puts Darwin Tsang's median patient age at 79, with 58% women.
Darwin Tsang's Medicare patients by age, 2024
CMS leaves out age groups with fewer than 11 patients.
Darwin Tsang's Medicare patients by sex, 2024
- Women10461%
- Men6639%
Chronic conditions among Darwin Tsang's Medicare patients, 2024
- High cholesterol75%
- High blood pressure57%
- Arthritis52%
- Ischemic heart disease25%
- Osteoporosis25%
- Anxiety21%
- Atrial fibrillation21%
- Mood disorders19%
Share of Medicare patients with each condition. A patient can have several.
Darwin Tsang's patients across all payers
Dmand AI patient panel data covers Medicare, Medicaid and commercial patients.
Patient panel by age, all payers
Median age 79
Patient panel by sex, all payers
- Women58%
- Men42%
Sources: Dmand AI Patient Panel Data; and Medicare Physician & Other Practitioners - by Provider (CMS), 2024 data
Darwin C. Tsang wrote 17 Medicare Part D claims in 2024
In 2024, Darwin Tsang wrote 17 Medicare Part D claims.
Source: Medicare Part D Prescribers - by Provider (CMS), 2024 data
How Darwin C. Tsang takes part in Medicare
Darwin Tsang 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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Darwin C. Tsang received $73 in industry payments in 2025
CMS Open Payments shows 2 general payments to Darwin Tsang from 1 drug or device company in 2025. Food and beverage make up the largest share, 100% of the total. Alcon Laboratories Inc paid the most, $73.
Companies that paid Darwin Tsang the most, 2025 to 2025
Share is of all general payments to this clinician.
Source: Open Payments (CMS), 2025 data, released July 7, 2026
Darwin C. Tsang graduated from New England College of Optometry
Darwin Tsang graduated from New England College of Optometry in 2015.
- Medical school
Source: Dmand AI Professional Profile Data
Sources for Darwin C. Tsang'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 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 (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 |
| 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 Darwin C. Tsang
Spotted something out of date? Email hello@dmand.ai and we will check the record. Contact details live in the free trial.
What is Darwin C. Tsang's NPI number?
Darwin C. Tsang's NPI number is 1619344918. It was assigned on August 21, 2015, and it is active in the NPI Registry.
What does Darwin C. Tsang specialize in?
Darwin C. Tsang is an optometrist in San Rafael, California. The primary specialty in the NPI Registry is Optometrist (taxonomy code 152W00000X).
Where does Darwin C. Tsang practice?
Darwin Tsang practices at 1001 Grand Ave, San Rafael, CA 94901. Darwin Tsang's primary practice is Marin Optometric Group, Inc in San Rafael, California. Dmand AI also links Darwin Tsang to 1 group practice or clinic and 1 medical group.
What is Darwin C. Tsang's office phone number?
The practice phone on file for Darwin Tsang is (415) 453-3812.
What is Darwin C. Tsang's medical license number?
Darwin Tsang holds California license 15225 TLG.
Does Darwin C. Tsang accept Medicare?
Yes. CMS lists Darwin Tsang as accepting Medicare assignment.
How many Medicare patients does Darwin C. Tsang see?
CMS counts 170 Medicare patients who saw Darwin Tsang in 2024, with an average age of 76.
Where did Darwin C. Tsang go to medical school?
Darwin Tsang graduated from New England College of Optometry in 2015.
Has Darwin C. Tsang received payments from drug or device companies?
CMS Open Payments shows $73 in general payments to Darwin Tsang from 1 company from 2025 to 2025. The largest total came from Alcon Laboratories Inc.
How long has Darwin C. Tsang been practicing?
Darwin Tsang graduated from medical school in 2015, 11 years ago.
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