1. Home
  2. Directory
  3. Connecticut
  4. New Haven
  5. Emergency Medicine
  6. NPI Profile

LONNIE SEO
NPI 1740785211
Emergency Medicine in New Haven, CT

Active since March 27, 2018PECOS EnrolledAccepts Medicare Assignment
464 CONGRESS AVE STE 260, NEW HAVEN, CT 06519(203) 737-2644 Get Directions Write a Review

NPPES record last updated: April 14, 2022. Verified against the NPPES registry weekly; last sync: October 18, 2026.

Record update history: Apr 14, 2022, Mar 27, 2018 (2 updates tracked since 2018).

About Lonnie Seo NPPES

Official registry information on file with the National Plan and Provider Enumeration System.

LONNIE SEO (NPI 1740785211) is an individual emergency medicine provider in New Haven, Connecticut, licensed in Connecticut (67025) and active in the NPI registry since March 2018. She is enrolled in Medicare PECOS, maintains a secondary practice location in Stamford, and is a graduate of Other (2018).

NPPES Registry Identity

NPI1740785211
Entity TypeIndividualFemale
Primary Taxonomy207P00000X
Provider Legal NameLONNIE SEO
Location Address464 CONGRESS AVE STE 260New Haven, CT 06519-1362
Mailing Address464 Congress Ave Ste 260New Haven, CT 06519-1362
Phone(203) 737-2644
Sole ProprietorNo
Medical School CMSOtherGraduated 2018
Enumeration DateMarch 27, 2018
Last NPPES UpdateApril 14, 20222 updates tracked since enumeration
NPPES CertifiedApril 14, 2022
✔ NPI 1740785211 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses 2

★ Primary SpecialtyEmergency MedicineAllopathic & Osteopathic Physicians
Taxonomy Code207P00000X
License✔ Licensed in CT · 67025
Definition
An emergency physician focuses on the immediate decision making and action necessary to prevent death or any further disability both in the pre-hospital setting by directing emergency medical technicians and in the emergency department. The emergency physician provides immediate recognition, evaluation, care, stabilization and disposition of a generally diversified population of adult and pediatric patients in response to acute illness and injury.
Also ListedStudent in an Organized Health Care Education/Training ProgramTaxonomy 390200000X
464 CONGRESS AVE STE 260, New Haven, CT 06519
Open in Google Maps ↗

Secondary Practice Location 1

Location 11 Hospital PlzStamford, CT 06902-3602 · Phone (201) 658-2042

Medicare Participation & PECOS CMS

Medicare enrollment, assignment, billing reassignment, and ordering and referring status from CMS.

Medicare Enrollment Status

✔

Enrolled in Medicare and accepts Medicare assignment

Lonnie Seo is registered in PECOS and agrees to accept the Medicare-approved amount as full payment. Medicare patients are not billed beyond the standard deductible and coinsurance.

PECOS PAC ID4486900982
PECOS Enrollment IDI20220425000810
Eligible to Order & Refer✔ Part B Labs & Imaging✔ Durable Medical Equipment✔ Home Health Agency✔ Power Mobility DevicesPer the CMS Ordering and Referring file. Eligibility means Medicare pays claims that this provider orders or refers for these categories.

Medicare Billing Reassignments

2

Medicare enrollment records show Lonnie Seo reassigns Medicare billing to 2 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.

Emergency Medicine Physicians Of New Haven County,llc
19 mi
Emergency Medicine
435 LEWIS AVE
Meriden, CT 06451
  • Reassigned Medicare billing, Connecticut enrollment
  • 69 clinicians in this Medicare group
NPI 1083910962 (203) 694-8200
Emergency Medicine Physicians Of Fairfield County, LLC
36 mi
Emergency Medicine
30 SHELBURNE RD
Stamford, CT 06902
  • Reassigned Medicare billing, Connecticut enrollment
  • 63 clinicians in this Medicare group
NPI 1689614109 (330) 493-4443

Source: CMS Revalidation Reassignment List, October 2026 release. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.

Areas of Expertise CMS Part B claims 8

Services this provider delivered to Medicare fee-for-service patients, from the CMS Medicare utilization data. Higher counts generally reflect more experience with a service; care delivered outside Medicare is not included.

Emergency department visit with high level of medical decision making 99285
An emergency department visit for severe conditions is when you urgently seek medical help due to serious health issues. These could be severe injuries, breathing problems, unbearable pain, or sudden severe illness. Doctors and nurses will provide immediate care to stabilize your condition.
302 services292 patients
Critical care, first 30-74 minutes 99291
Critical care involves immediate and constant attention by a team of specially-trained health professionals. It's for patients with life-threatening conditions, requiring first 30-74 minutes of intense monitoring and treatment.
148 services143 patients
Emergency department visit with moderate level of medical decision making 99284
An emergency department visit for a high-severity issue means you're experiencing a serious health problem that needs immediate attention. This could be a severe injury, serious illness, or life-threatening condition. Medical professionals will provide urgent care to stabilize your condition.
119 services117 patients
Emergency department visit with low level of medical decision making 99283
An emergency department visit for a problem of moderate severity involves immediate medical attention for issues like minor fractures, burns, or high fever. The healthcare team will assess your condition, provide necessary treatment, and may suggest further tests or admission if required.
43 services39 patients
Established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more 99213
This is a routine visit for patients who have already been seen by the healthcare provider. During this approximately 20-29 minute appointment, your health status will be evaluated and any necessary treatments or tests will be discussed. It's a chance to address any health concerns you may have.
15 services15 patients
Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more 99214
This is a routine check-up for patients who have previously visited our clinic. It involves a comprehensive review of your health and any ongoing treatments. The consultation lasts between 30-39 minutes, allowing enough time to discuss any concerns.
14 services14 patients

Physician Visit Costs CMS claims · ZIP area

Typical Medicare office-visit costs in the 06519 ZIP code area, from fee-for-service claims. These are area statistics, not this provider’s prices; actual charges vary by service and coverage.

New Patient
$93.86 typical visit price
range $60.82 – $183.10
Typical copayment $23.46 (range $15.20 – $45.77)
Most-billed visit code 99203
Established Patient
$106.68 typical visit price
range $19.76 – $149.26
Typical copayment $26.67 (range $4.94 – $37.31)
Most-billed visit code 99214
Amounts reflect what Medicare beneficiaries in this ZIP area are typically charged for office visits. Patients with other coverage should check their individual plans.

Other Providers at the Same Location NPPES 20

Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.

MEGHAN ELIZABETH GWARA PA-C
Physician Assistant (Medical)
464 CONGRESS AVE STE 260
NEW HAVEN, CT 06519
South Central Connecticut Planning Region (203) 785-4404
DR. EDWARD ROBERT MELNICK M.D.
Emergency Medicine
464 CONGRESS AVE STE 260, YALE UNIV SCHOOL OF MED, DEPT OF EMERGENCY MEDICINE
NEW HAVEN, CT 06519
South Central Connecticut Planning Region (203) 772-6664
AISHA EDITH DROZ LOPEZ MD
Emergency Medicine
464 CONGRESS AVE STE 260
NEW HAVEN, CT 06519
South Central Connecticut Planning Region (203) 785-2353
SEAN P BUSH M.D.
Emergency Medicine
464 CONGRESS AVE STE 260
NEW HAVEN, CT 06519
South Central Connecticut Planning Region (252) 917-9311
GREGORY LUKE LARKIN MD
Emergency Medicine
464 CONGRESS AVE STE 260
NEW HAVEN, CT 06519
South Central Connecticut Planning Region (203) 785-2353
ZAINAB RASHEED
Physician Assistant (Medical)
464 CONGRESS AVE STE 260
NEW HAVEN, CT 06519
South Central Connecticut Planning Region (571) 388-8353
DR. SHEEJA THOMAS MD
Emergency Medicine
464 CONGRESS AVE STE 260, YALE-NEW HAVEN HOSPITAL DEPT EMERGENCY MEDICINE
NEW HAVEN, CT 06519
South Central Connecticut Planning Region (203) 785-2353
MRS. CAITLYN MCNAMARA MCNIFF PA
Physician Assistant
464 CONGRESS AVE STE 260
NEW HAVEN, CT 06519
South Central Connecticut Planning Region (203) 785-4404

Frequently Asked Questions NPPES & CMS

Common questions about this NPI record, answered from the official NPPES registry and CMS datasets shown on this page.

What is Lonnie Seo's NPI number?

The NPI number for Lonnie Seo is 1740785211. It was assigned to this individual provider in the NPPES registry on March 27, 2018.

Where is Lonnie Seo located?

Lonnie Seo practices at 464 Congress Ave Ste 260, New Haven, CT 06519. The listed phone number is (203) 737-2644.

What is Lonnie Seo's specialty?

The primary specialty registered for this NPI is Emergency Medicine with taxonomy code 207P00000X.

Is Lonnie Seo enrolled in Medicare?

Yes. Lonnie Seo is registered in the Medicare PECOS system and accepts Medicare assignment, which means accepting the Medicare-approved amount as payment in full for covered services.

Which organizations bill Medicare for Lonnie Seo's services?

According to the CMS Revalidation Reassignment List (October 2026 release), Lonnie Seo reassigns Medicare benefits to 2 organizations: Emergency Medicine Physicians Of New Haven County,llc (Meriden, CT) and Emergency Medicine Physicians Of Fairfield County, LLC (Stamford, CT). Each reassignment is filed with Medicare on form CMS-855R, signed by both the clinician and the organization, and lets the organization bill Medicare and receive payment for Lonnie Seo's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.

When was this NPI record last updated?

The NPPES record for Lonnie Seo was last updated on April 14, 2022. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 4 years ago. If this record has changed at CMS more recently, you can request an on-demand re-check against the live CMS registry, directly from this page.