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

Gretta Mae Colby, MD

Individual provider Internal Medicine Physician · NPI 1306587639

Gretta Mae Colby, MD is an Internal Medicine in Milwaukee, Wisconsin. Graduated from Medical College of Wisconsin in 2022, 4 years ago. Practices with Aurora Medical Group, Inc, a 3,741-clinician group and accepts Medicare assignment. Licensed in Wisconsin.

Years since qualifying
4
Trained at
Medical College of Wisconsin
Licensed in
WI
In the registry since
2022
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

945 N 12th St
Milwaukee, WI 53233-1305
Phone: (414) 219-7427
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Internal Medicine Physician (primary) Taxonomy 207R00000X · Licence 83738-20 (WI)

Record details

NPI number1306587639
Entity typeIndividual (Type 1)
GenderFemale
Credentials MD
Sole proprietorYes
NPI enumeratedApril 1, 2022
Last updated in NPPESSeptember 18, 2025
Certification dateSeptember 18, 2025

Medicare enrollment

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

Medicare specialtyINTERNAL MEDICINE
Medical schoolMEDICAL COLLEGE OF WISCONSIN
Graduated 2022 (4 years in practice)
Group practice Aurora Medical Group, Inc. — 3741 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount

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