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Obstetrics/Gynecology

Julia Geynisman-Tan, MD

Works at hospitals in Winfield, IL · Geneva, IL · McHenry, IL … · Illinois

Summary

Dr. Julia Geynisman-Tan, MD is an OB-GYN at 1200 N Westmoreland Rd, Suite 100, Lake Forest, IL 60045. Phone: (847) 735-8500. Accepts Medicare assignment. In 2024, Julia Geynisman-Tan had 519 Original Medicare patients and 14,908 services. NPI 1831465806. 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.

From official Medicare data

This page shows what Medicare's official clinician data says about Julia Geynisman-Tan, 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 Julia Geynisman-Tan accept Medicare assignment?
Yes. Medicare's clinician data says Julia Geynisman-Tan 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 Julia Geynisman-Tan see?
In 2024, CMS data shows 519 Original Medicare patients and 14,908 services for Julia Geynisman-Tan. This counts Original Medicare only and measures volume, not quality.
What is Julia Geynisman-Tan's NPI number?
1831465806. 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 Julia Geynisman-Tan, 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 patients519
Services billed to Medicare14,908
Different services or procedures50
Participating Medicare providerYes
Average age of these patients75

Most frequent services

  1. Injection, onabotulinumtoxina, 1 unit (J0585)13,200 services
  2. Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more (99214)374 services
  3. Automated urinalysis test (81003)257 services
  4. Insertion of temporary bladder tube (51701)252 services
  5. New patient office or other outpatient visit with moderate level of medical decision making, if using time, 45 minutes or more (99204)195 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 cholesterol74%
  • High blood pressure65%
  • Arthritis57%
  • Anxiety30%
  • Osteoporosis27%
  • Depression24%

Hospitals where Julia Geynisman-Tan works

Medicare's Facility Affiliation Data lists Julia Geynisman-Tan 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 Julia Geynisman-Tan is enrolled with Medicare (CMS data updated October 2, 2026). The first 5 of 16; the Medicare profile lists all.

Group practices

Medicare enrollment lists Julia Geynisman-Tan as a member of these groups (CMS data updated October 2, 2026).

  • Northwestern Medical Faculty Foundation4,503 clinicians in the group
  • Central Dupage Physician Group1,080 clinicians in the group

Specialties

Find other Obstetrics/Gynecology doctors in Illinois →

Other OB-GYNs in Lake Forest

Clinicians with the same Medicare primary specialty in Lake Forest, IL — not a recommendation.

All OB-GYNs in Lake Forest →

Other clinicians in Northwestern Medical Faculty Foundation

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

Clinician information

CredentialMD
Medical schoolUniversity Of Michigan Medical School
Graduation year2012 (14 years since medical school)
Gender (as listed)Female
Medicare assignmentAccepts (Medicare-approved amount as full payment)
TelehealthOffers telehealth services
NPI (National Provider Identifier)1831465806
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