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Family Practice

Katherine D. Oyster, MD

Works at hospitals in Saint Paul, MN · Minnesota

Summary

Dr. Katherine D. Oyster, MD is a family doctor at 440 Elm St E, Annandale, MN 55302. Phone: (320) 682-5225. Accepts Medicare assignment. In 2024, Katherine D. Oyster had 71 Original Medicare patients and 626 services. NPI 1902245681. Source: CMS National Downloadable File, updated October 2, 2026; CMS Facility Affiliation Data, updated October 2, 2026; CMS Medicare Physician & Other Practitioners, data year 2024.

  • Specialty: Family doctor (Medicare lists Family Practice)
  • Address: 440 Elm St E, Annandale, MN 55302 · Directions
  • Phone: (320) 682‑5225
  • Medicare: Accepts Medicare assignment
  • Hospital: Allina United Hospital
  • Group practice: Allina Health System
  • Medical school: Medical College Of Wisconsin · graduated 2013 (13 years since medical school)
  • Gender (as listed): Female

From official Medicare data

This page shows what Medicare's official clinician data says about Katherine D. Oyster, joined by NPI number (data updated October 2, 2026). It is not a recommendation or a rating. Call the office or hospital to confirm before you go.

In a medical emergency, call 911.

Quick answers

Does Katherine D. Oyster accept Medicare assignment?
Yes. Medicare's clinician data says Katherine D. Oyster accepts Medicare assignment (the Medicare-approved amount as full payment for covered services), as of October 2, 2026. Ask the office to confirm before your visit.
How many Medicare patients does Katherine D. Oyster see?
In 2024, CMS data shows 71 Original Medicare patients and 626 services for Katherine D. Oyster. This counts Original Medicare only and measures volume, not quality.
What is Katherine D. Oyster's NPI number?
1902245681. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.

Medicare activity in 2024

Official CMS public-use data for Katherine D. Oyster, data year 2024 (released May 21, 2026). It covers Original Medicare (fee-for-service) patients only, not Medicare Advantage or other insurance. It shows volume, not quality or outcomes. CMS hides any count of 10 or fewer patients.

Original Medicare patients71
Services billed to Medicare626
Different services or procedures78
Participating Medicare providerYes
Average age of these patients65

Most frequent services

  1. Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more (99214)31 services
  2. Insertion of needle into vein for collection of blood sample (36415)28 services
  3. Admn sarscov2 vacc 1 dose (90480)17 services
  4. Sarscov2 vac 50 mcg/0.5ml im (91322)17 services
  5. Administration of influenza virus vaccine (G0008)16 services

Chronic conditions among these patients

Share of this clinician’s Original Medicare patients with each condition, as published by CMS (it describes the patients, not the care given).

  • High cholesterol52%
  • High blood pressure48%
  • Anxiety31%
  • Diabetes28%
  • Depression25%
  • Arthritis23%

Hospitals where Katherine D. Oyster works

Medicare's Facility Affiliation Data lists Katherine D. Oyster at these hospitals (updated October 2, 2026). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians. Star rating and emergency services: Hospital General Information (CMS), data updated October 26, 2026.

Practice locations

Addresses where Katherine D. Oyster is enrolled with Medicare (CMS data updated October 2, 2026).

Group practices

Medicare enrollment lists Katherine D. Oyster as a member of this group (CMS data updated October 2, 2026).

  • Allina Health System3,842 clinicians in the group

Specialties

Find other Family Practice doctors in Minnesota →

Other family doctors in Annandale

Clinicians with the same Medicare primary specialty in Annandale, MN — not a recommendation.

All family doctors in Annandale →

Other clinicians in Allina Health System

Medicare enrollment lists these clinicians in the same group practice — not a recommendation.

Clinician information

CredentialMD
Medical schoolMedical College Of Wisconsin
Graduation year2013 (13 years since medical school)
Gender (as listed)Female
Medicare assignmentAccepts (Medicare-approved amount as full payment)
NPI (National Provider Identifier)1902245681
CorrectionsReport an error or suggest an update →

Most corrections must be made at the source: clinicians update their NPI Registry record (NPPES) and their Medicare enrollment (PECOS); this page follows the next data release.

Sources

  1. Facility Affiliation Data — Centers for Medicare & Medicaid Services (CMS), data updated October 2, 2026, retrieved October 29, 2026
  2. Hospital General Information — CMS, data updated October 26, 2026, retrieved November 13, 2026
  3. National Downloadable File (Doctors and Clinicians) — CMS, data updated October 2, 2026, retrieved October 29, 2026
  4. Medicare Physician & Other Practitioners - by Provider — CMS, data year 2024, released May 21, 2026; Medicare Physician & Other Practitioners - by Provider and Service
  5. NPI Registry — U.S. Department of Health and Human Services (NPPES), the clinician’s official record
  6. Medicare Care Compare — official Medicare tool to look up clinicians