Provider records sourced from NPPES (CMS National Plan & Provider Enumeration System). Data current as of August 10, 2026.

Dr. William Sprague Trask IV, DO

Individual provider Anesthesiology Physician · NPI 1184706608

Dr. William Sprague Trask IV, DO is an Anesthesiology in Boulder, Colorado. Graduated from At Still University of Health Sciences, College of Osteo Med, Kirksville in 2006, 20 years ago. Practices with Boulder Valley Anesthesiology, PLLC, a 60-clinician group, works from 2 locations and accepts Medicare assignment. Licensed in Colorado and Washington.

Years since qualifying
20
Trained at
At Still University of Health Sciences, College of Osteo Med, Kirksville
Licensed in
CO, WA
In the registry since
2006
Specialties on file
3
What do these letters mean?
DO — Doctor of Osteopathic Medicine
A fully licensed physician, trained like an MD with additional musculoskeletal training. Equivalent practice rights in all 50 states.

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Practice location Address checks out

4747 Arapahoe Ave
Boulder, CO 80303-1131
Phone: (303) 415-2532
Fax: (303) 785-1725
Show map & directions

Pin is approximate — placed at the ZIP-code centre, not the exact door.

Additional practice locations (1)

  • 12040 Ne 128th St, Kirkland, WA 98034-3013 — (425) 899-3455

Specialties & licences

Anesthesiology Physician (primary) Taxonomy 207L00000X · Licence 49491 (CO)
Anesthesiology Physician Taxonomy 207L00000X · Licence OL20000111 (WA)
Anesthesiology Physician Taxonomy 207L00000X · Licence OP60150344 (WA)

Record details

NPI number1184706608
Entity typeIndividual (Type 1)
GenderMale
Credentials DO
Sole proprietorNo
NPI enumeratedOctober 20, 2006
Last updated in NPPESMarch 2, 2019
Mailing addressPo Box 21147, Boulder, CO 80308-4147

Medicare enrollment

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

Medicare specialtyANESTHESIOLOGY
Medical schoolAT STILL UNIVERSITY OF HEALTH SCIENCES, COLLEGE OF OSTEO MED, KIRKSVILLE
Graduated 2006 (20 years in practice)
Group practice Boulder Valley Anesthesiology, Pllc — 60 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount

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