Provider records sourced from NPPES (CMS National Plan & Provider Enumeration System). Data current as of August 10, 2026.
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Martha Sierra Diaz, PA-C

Individual provider Physician Assistant · NPI 1538481882

Martha Sierra Diaz, PA-C is a Physician Assistant in New Haven, Connecticut. Graduated from Js Weill Medical College, Cornell University in 1995, 31 years ago. Practices with Yale University, a 2,618-clinician group and accepts Medicare assignment. Licensed in Connecticut and Michigan.

Years since qualifying
31
Trained at
Js Weill Medical College, Cornell University
Licensed in
CT, MI
In the registry since
2010
Specialties on file
2
What do these letters mean?
PA-C — Physician Assistant, Certified
A physician assistant who holds current national certification.

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Practice location Address checks out

25 Park St NP1 Smilow Cancer Hospital/ynhh
New Haven, CT 06519-1110 Not confirmed with CMS for 11 years — call before visiting
Phone: (203) 200-4176
Fax: (203) 200-5075
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Physician Assistant (primary) Taxonomy 363A00000X · Licence 000762 (CT)
Physician Assistant Taxonomy 363A00000X · Licence 5601005665 (MI)

Record details

NPI number1538481882
Entity typeIndividual (Type 1)
GenderFemale
Credentials PA-C
Sole proprietorNo
NPI enumeratedFebruary 26, 2010
Last updated in NPPESMarch 31, 2015

Medicare enrollment

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

Medicare specialtyPHYSICIAN ASSISTANT
Medical schoolJS WEILL MEDICAL COLLEGE, CORNELL UNIVERSITY
Graduated 1995 (31 years in practice)
Group practice Yale University — 2618 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount
Practice locations2 on file with Medicare

Medicare patients and services, 2024

From the CMS Medicare Physician & Other Practitioners file for calendar year 2024. It counts Original Medicare patients only, so a practice that mostly sees Medicare Advantage or privately insured patients looks smaller here than it is.

Medicare patients116
Services billed 458 a service is one billed item, such as a visit, a test or a procedure
Average patient age73

Dollar amounts are not shown. What Medicare pays a practice is gross billings, before staff, premises and tax and including the cost of any drugs it administers, so it is not what a clinician earns.

Practises at

Facilities the CMS Facility Affiliation file lists for this clinician.

Colleagues at Yale University

Clinicians the CMS Doctors & Clinicians file lists under the same group practice. CMS counts 2618 clinicians in the practice; 12 are shown here.

Other providers in New Haven