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

William Brian Greiser, MD

Individual provider Emergency Medicine Physician · NPI 1720114408

William Brian Greiser, MD is an Emergency Medicine Physician in Trinidad, Colorado. Licensed in Colorado. Registered with an NPI since 2007.

Licensed in
CO
In the registry since
2007
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

410 Benedicta Ave
Trinidad, CO 81082-2005 Not confirmed with CMS for 19 years — call before visiting
Phone: (800) 893-9698
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Emergency Medicine Physician (primary) Taxonomy 207P00000X · Licence 36079 (CO)

Record details

NPI number1720114408
Entity typeIndividual (Type 1)
GenderMale
Credentials MD
Sole proprietorNo
NPI enumeratedFebruary 26, 2007
Last updated in NPPESJuly 8, 2007

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 patients37
Services billed 49 a service is one billed item, such as a visit, a test or a procedure
Average patient age72

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.

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