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

Dr. Mark G Oas, DC

Individual provider Chiropractor · NPI 1487648093

Dr. Mark G Oas, DC is registered under Chiropractic in Eau Claire, Wisconsin. Graduated from Northwestern College of Chiropractic in 2001, 25 years ago. Accepts Medicare assignment. Licensed in Wisconsin.

Years since qualifying
25
Trained at
Northwestern College of Chiropractic
Licensed in
WI
In the registry since
2005
What do these letters mean?
DC — Doctor of Chiropractic
A licensed chiropractor.

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Practice location Address checks out

1740 Westgate Rd
Eau Claire, WI 54703-4963 Not confirmed with CMS for 15 years — call before visiting
Phone: (715) 552-7889
Fax: (715) 552-7939
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Chiropractor (primary) Taxonomy 111N00000X · Licence 3823-012 (WI)

Record details

NPI number1487648093
Entity typeIndividual (Type 1)
GenderMale
Credentials DC
Sole proprietorNo
NPI enumeratedSeptember 9, 2005
Last updated in NPPESJune 22, 2011

Medicare enrollment

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

Medicare specialtyCHIROPRACTIC
Medical schoolNORTHWESTERN COLLEGE OF CHIROPRACTIC
Graduated 2001 (25 years in practice)
Accepts Medicare assignment Yes — accepts the Medicare-approved amount

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 patients62
Services billed 436 a service is one billed item, such as a visit, a test or a procedure
Average patient age65

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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