Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Dr. Ruth Callaway Warren, DO

Medical Oncology Physician in Green Bay, WI · enumerated 2006.

Data current as of Jul 13, 2026 · sourced from CMS NPPES

National Provider Identifier

1124096185

Verified

See something wrong? Report a correction

Registry record

Entity type Individual (Type 1)

Name Dr. Ruth Callaway Warren

Credential DO

Sex Female

Practice address 1726 Shawano Ave, Green Bay, WI, 54303

Phone (920) 884-3135

Fax (920) 884-3144

Enumeration date Mar 8, 2006

Last updated in NPPES Dec 20, 2021

Taxonomy & licenses

207RX0202X Medical Oncology Physician Allopathic & Osteopathic Physicians · License 5101018539 (MI) Secondary

207RX0202X Medical Oncology Physician Allopathic & Osteopathic Physicians · License 50362 (WI) Primary

DO · Doctor of Osteopathic Medicine: A fully licensed physician trained in osteopathic medical schools, with the same practice rights as an MD. About the DO credential

Other identifiers

Identifier	Type	State	Issuer
1124096185	Other	WI	BCBS ANTHEM
1124096185	Medicaid	MI	-
100004011	Medicaid	WI	-

What is an NPI number?

A National Provider Identifier (NPI) is a unique 10-digit number that CMS assigns to every U.S. healthcare provider and organization under HIPAA. Type 1 NPIs identify individual providers; Type 2 NPIs identify organizations. The NPI appears on insurance claims, prescriptions, and credentialing paperwork, and never changes, even if the provider moves or changes specialty.

Read the full guide → Validate an NPI →

Frequently asked questions

Is this the official NPI registry?

No. NPI Portal is a private site built on public CMS NPPES data. The official registry is npiregistry.cms.hhs.gov, operated by CMS.

What specialty is Ruth Warren?

Ruth Warren is registered in NPPES with the primary taxonomy of Medical Oncology Physician. The taxonomy code describes the provider's classification and area of specialization for claims and credentialing.

Other providers at this practice address

Browse all →

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2021-12-20.