Provider records sourced from NPPES (CMS National Plan & Provider Enumeration System). Data current as of October 4, 2026.
NPIDirectory

Althea Marie Fernandez Diaz, MD

Individual provider Allergy & Immunology Physician · NPI 1649838640

Althea Marie Fernandez Diaz, MD practises Allergy/Immunology in Brewster, New York. Graduated from New York Medical College in 2019, 7 years ago. Practices with Optum Medical Care PC, a 1,018-clinician group and accepts Medicare assignment. Licensed in New York.

Years since qualifying
7
Trained at
New York Medical College
Licensed in
NY
In the registry since
2019
Specialties on file
2
What do these letters mean?
MD — Doctor of Medicine
A physician who completed allopathic medical school.

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Practice location Address checks out

185 Ny 312 Southeast Executive Park
Brewster, NY 10509
Phone: (845) 278-7000
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Allergy & Immunology Physician (primary) Taxonomy 207K00000X · Licence 316128 (NY)
Internal Medicine Physician Taxonomy 207R00000X · Licence 316128 (NY)

Record details

NPI number1649838640
Entity typeIndividual (Type 1)
GenderFemale
Credentials MD
Sole proprietorNo
NPI enumeratedJune 4, 2019
Last updated in NPPESApril 14, 2026
Certification dateApril 14, 2026

Medicare enrollment

From the CMS Doctors & Clinicians file — this clinician is enrolled in Medicare.

Medicare specialtyALLERGY/IMMUNOLOGY
Medical schoolNEW YORK MEDICAL COLLEGE
Graduated 2019 (7 years in practice)
Group practice Optum Medical Care Pc — 1018 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount

Payments from drug and device companies, 2025

Drug and device makers are required by federal law (the Physician Payments Sunshine Act) to report what they pay or give to clinicians, and CMS publishes the reports as Open Payments. This is the 2025 program year. A report is a record of a payment, not an allegation of anything, and many are small items such as meals. Only general payments are listed here; research payments and ownership or investment interests are reported separately by CMS and are not shown.

Food and Beverage $15 1 payment · a meal or drink at a meeting or visit, not a fee

Each amount is the sum of what companies reported for that kind of payment in 2025, rounded to the dollar. Not all of it is income to the clinician: a meal is not a fee, a charitable contribution goes to a charity, and a royalty or an acquisition payment is not a salary.

Check a report, or dispute one, at the source in CMS’s own tool, Open Payments. Corrections go through CMS’s dispute process. This site removes a home address on request and asks for no proof, because that is privacy; it will not remove an accurate payment report on request, because that is a statutory public disclosure.

Colleagues at Optum Medical Care PC

Clinicians the CMS Doctors & Clinicians file lists under the same group practice. CMS counts 1018 clinicians in the practice; 12 are shown here.