Recently Updated NPI Information — some details in this NPI profile have been updated in the NPI registry within the last 60 days.

MR. WILLIAM AARON KAY MD
NPI 1700094307
Internal Medicine - Adult Congenital Heart Disease in Fairfield, OH

Q: What is William Kay's NPI number?

The NPI number for William Kay is 1700094307. It was assigned to this individual provider in the NPPES registry on May 18, 2007.

Q: What is William Kay's specialty?

The primary specialty registered for this NPI is Internal Medicine, specializing in Adult Congenital Heart Disease, with taxonomy code 207RA0002X.

Q: When was this NPI record last updated?

The NPPES record for William Kay was last updated on September 30, 2026. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 33 days 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.

Active since May 18, 2007PECOS EnrolledAccepts Medicare Assignment

3000 MACK RD STE 100, FAIRFIELD, OH 45014(513) 751-4222(513) 874-3023 Get Directions Write a Review

NPPES record last updated: September 30, 2026. Verified against the NPPES registry weekly; last sync: October 25, 2026.

Record update history: Sep 30, 2026, Nov 20, 2023, Mar 17, 2021 and 1 more (4 updates tracked since 2020).

On this page

About Mr. William Aaron Kay Md NPPES

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

MR. WILLIAM AARON KAY MD (NPI 1700094307) is an individual adult congenital heart disease provider in Fairfield, Ohio, licensed in Ohio (35.087717) and active in the NPI registry since May 2007. He is enrolled in Medicare PECOS, is affiliated with The Jewish Hospital-mercy Health, and maintains a secondary practice location in Lafayette.

NPPES Registry Identity

NPI1700094307

Entity TypeIndividualMale

Primary Taxonomy207RA0002X

Provider Legal NameMR. WILLIAM AARON KAYCredential: MD

Location Address3000 MACK RD STE 100Fairfield, OH 45014-5335

Mailing Address3000 Mack Rd Ste 100Fairfield, OH 45014-5335 · (513) 751-4222 · Fax (513) 874-3023

Phone(513) 751-4222

Fax(513) 874-3023

Sole ProprietorNo

Medical School CMSIndiana University School Of MedicineGraduated 2004

Enumeration DateMay 18, 2007

Last NPPES UpdateSeptember 30, 20264 updates tracked since enumeration

NPPES CertifiedSeptember 30, 2026

✔ NPI 1700094307 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses 3

★ Primary SpecialtyInternal Medicine · Adult Congenital Heart DiseaseAllopathic & Osteopathic Physicians

Taxonomy Code207RA0002X

License✔ Licensed in OH · 35.087717

Definition

A physician who specializes in the care and treatment of adults with congenital heart disease. Adult congenital heart disease (ACHD) physicians are trained to understand the complexities of congenital heart disease, anatomy, physiology, surgical repairs, and long-term complications and use that to manage ACHD with acquired heart disease, including heart failure, arrhythmias, and pulmonary hypertension.

Also ListedInternal Medicine · Cardiovascular DiseaseTaxonomy 207RC0000X · License 01072677A (IN)

Also ListedStudent in an Organized Health Care Education/Training ProgramTaxonomy 390200000X · License 35.087717 (OH)

3000 MACK RD STE 100, Fairfield, OH 45014

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Secondary Practice Location 1

Location 13900 St Francis Way Ste 200Lafayette, IN 47905-4940 · Phone (317) 962-9700 · Fax (317) 962-9704

Other Identifiers 1

Medicaid201157870IN

Accepted Insurance

The full list of accepted plans is on the Insurance tab. Issuers include Ambetter from Buckeye Health Plan, Ambetter from Meridian, Ambetter Health and more.Insurance ›

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

Mr. William Aaron Kay Md 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 ID4587822861

PECOS Enrollment IDI20120215000621

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

Medicare enrollment records show William Kay reassigns Medicare billing to 3 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.

Mercy Health Physicians Cincinnati Specialty Care LLC

8.8 mi

Surgery

4600 MCAULEY PL STE 600
Blue Ash, OH 45242

Reassigned Medicare billing, Ohio enrollment
481 clinicians in this Medicare group

NPI 1154942795 (888) 696-3541

Indiana University Health, Inc

94 mi

Cardiovascular Disease

1701 N SENATE BLVD
Indianapolis, IN 46202

Reassigned Medicare billing, Indiana enrollment
148 clinicians in this Medicare group

NPI 1376586719 (317) 962-2000

University Medical Diagnostic Associates, Inc.

94 mi

Internal Medicine

1701 N SENATE BLVD
Indianapolis, IN 46202

Reassigned Medicare billing, Indiana enrollment
358 clinicians in this Medicare group

NPI 1861441537 (317) 274-8660

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 22

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.

Routine electrocardiogram (ecg) using at least 12 leads with interpretation and report only 93010

A routine electrocardiogram (ECG) with 12 leads is a simple, non-invasive test that records the electrical activity of your heart. It helps in identifying heart conditions by detecting irregularities in your heart rhythms. The results are interpreted and a report is provided.

890 services707 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.

185 services136 patients

Ultrasound of heart with color-depicted blood flow, rate, direction and valve function 93306

This is a heart ultrasound, also known as an echocardiogram. It uses sound waves to create pictures of your heart, showing how blood flows through it. The color depicts the blood flow's speed and direction. It also checks the heart's valves to ensure they're working properly.

163 services162 patients

Routine electrocardiogram (ecg) using at least 12 leads with interpretation and report 93000

An electrocardiogram (ECG) is a non-invasive test that records your heart's electrical activity. Using 12 leads attached to your body, it captures data to help identify heart conditions. A doctor interprets the results and provides a report.

137 services128 patients

Ultrasound of heart with color-depicted blood flow, rate, direction and valve function 93306

83 services82 patients

Initial hospital care with moderate level of medical decision making, if using time, at least 75 minutes 99223

Initial hospital inpatient care per day, typically 70 minutes, refers to the daily medical service provided to patients admitted to the hospital. This includes a comprehensive evaluation, diagnosis, treatment plan, and monitoring of your health condition. It ensures your well-being during your hospital stay.

83 services83 patients

Subsequent hospital care with moderate levelof medical decision making, if using time, at least 50 minutes 99233

Follow-up hospital inpatient care per day typically involves a 35-minute check-up by your healthcare provider. This service includes monitoring your health progress, adjusting your treatment plan if needed, and answering any questions you may have about your condition or care.

53 services40 patients

New patient office or other outpatient visit with moderate level of medical decision making, if using time, 45 minutes or more 99204

This is a first-time office or outpatient visit lasting between 45-59 minutes. The healthcare provider evaluates your health, discusses your medical history, and may suggest further tests or treatments. It's an opportunity to ask questions and understand your health better.

37 services37 patients

Ultrasound of heart with color-depicted blood flow, rate and valve function 93325

An ultrasound of the heart, also known as an echocardiogram, uses sound waves to create pictures of your heart. It shows the structure, movement, and blood flow within your heart. This helps assess the heart's health and function, including the valves and rate.

31 services30 patients

Established patient office or other outpatient visit with high level of medical decision making, if using time, 40 minutes or more 99215

This service involves a follow-up appointment for existing patients, lasting between 40 to 54 minutes. During this time, your healthcare provider will assess your current health status, discuss any changes or concerns, review your treatment plan, and answer any questions you may have.

31 services26 patients

Ultrasound of heart, follow-up 93308

A follow-up ultrasound of the heart, also known as an echocardiogram, is a non-invasive test that uses sound waves to create images of your heart. It helps doctors monitor your heart's function and structures after initial assessment or treatment.

21 services19 patients

Ultrasound of heart with color-depicted blood flow, rate and valve function 93325

18 services17 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.

18 services11 patients

Ultrasound of heart blood flow, valves and chambers, follow-up 93321

This procedure, an echocardiogram, uses sound waves to create images of your heart. It aids in assessing your heart's blood flow, chambers, and valves. It's a follow-up procedure, ensuring that your heart is functioning properly post-treatment.

15 services15 patients

Subsequent hospital care with moderate levelof medical decision making, if using time, at least 35 minutes 99232

Follow-up hospital inpatient care involves daily check-ups while you're admitted in the hospital. Typically, a healthcare provider spends about 25 minutes each day reviewing your condition, adjusting treatment if needed, and answering any questions you might have.

15 services15 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.

13 services13 patients

Initial hospital care with straightforward or low-level medical decision making, if using time, at least 55 minutes 99222

Initial hospital inpatient care is a service where a healthcare provider spends about 50 minutes per day overseeing your care while you're admitted in the hospital. This includes reviewing your health status, planning your treatment, and ensuring your safety and comfort.

13 services13 patients

Ultrasound of heart with probe in esophagus, with report 93312

This procedure, called a transesophageal echocardiogram, uses a small probe passed into your esophagus to capture detailed images of your heart. The report provides information about your heart's structure and function.

12 services12 patients

Ultrasound of heart blood flow, valves and chambers, follow-up 93321

12 services11 patients

Use of a drug to induce depression of consciousness by physician performing a procedure (5 years or older), initial 15 minutes 99152

This procedure involves a doctor administering a medication to reduce your consciousness during a procedure. This helps in managing discomfort and anxiety. The initial application lasts for 15 minutes and is for individuals aged 5 years or older.

12 services12 patients

New patient office or other outpatient visit with a high level of medical decision making, if using time, 60 minutes or more 99205

This is a first-time patient visit where a healthcare professional spends 60-74 minutes with you. It involves a comprehensive evaluation, including your medical history and current health condition. They'll also advise on preventive health measures and formulate a treatment plan if needed.

12 services12 patients

Heart muscle strain imaging 93356

Heart muscle strain imaging is a non-invasive test that uses sound waves to create pictures of your heart. It helps doctors evaluate how well your heart muscle is working and detect any damage or disease. This can aid in diagnosing heart conditions and guiding treatment plans.

11 services11 patients

Hospital Affiliations CMS Care Compare 4

Hospitals where this provider delivers care, identified from recent Medicare claims and place-of-service records.

The Jewish Hospital-Mercy Health

Acute Care Hospitals · Cincinnati, OH

4/5 CMS rating

OwnershipVoluntary non-profit - Private

CMS Certification Number360016

Location4777 East Galbraith RoadCincinnati, OH 45236 · Hamilton County

Emergency services

Mercy Health - Fairfield Hospital

Acute Care Hospitals · Fairfield, OH

3/5 CMS rating

OwnershipVoluntary non-profit - Private

CMS Certification Number360056

Location3000 Mack RoadFairfield, OH 45014 · Butler County

Emergency services Birthing friendly

Mercy Health - West Hospital

Acute Care Hospitals · Cincinnati, OH

4/5 CMS rating

OwnershipVoluntary non-profit - Private

CMS Certification Number360234

Location3300 Mercy Health BlvdCincinnati, OH 45211 · Hamilton County

Emergency services Birthing friendly

Mercy Health - Clermont Hospital

Acute Care Hospitals · Batavia, OH

4/5 CMS rating

OwnershipVoluntary non-profit - Church

CMS Certification Number360236

Location3000 Hospital DriveBatavia, OH 45103 · Clermont County

Emergency services

Other Providers at the Same Location NPPES 15

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

NATASHA NICOLE NEIS NP

Nurse Practitioner (Acute Care)