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

DR. WILLIAM SPENCER GRIGG D.O.
NPI 1578050266
Internal Medicine - Clinical Cardiac Electrophysiology in Mountain Home, AR

Active since April 18, 2018PECOS EnrolledAccepts Medicare Assignment
88.22/100
CMS Quality Rating
555 W 6TH ST, MOUNTAIN HOME, AR 72653(870) 425-8288(870) 425-8299 Get Directions Write a Review

NPPES record last updated: August 13, 2026. Verified against the NPPES registry weekly; last sync: August 30, 2026.

Record update history: Aug 13, 2026, Jul 22, 2024, Jan 26, 2022 and 3 more (6 updates tracked since 2018).

About Dr. William Spencer Grigg D.o. NPPES

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

DR. WILLIAM SPENCER GRIGG D.O. (NPI 1578050266) is an individual clinical cardiac electrophysiology provider in Mountain Home, Arkansas, licensed in Arkansas (E18962) and active in the NPI registry since April 2018. He is enrolled in Medicare PECOS and is a graduate of Other (2018).

NPPES Registry Identity

NPI1578050266
Entity TypeIndividualMale
Primary Taxonomy207RC0001X
Provider Legal NameDR. WILLIAM SPENCER GRIGGCredential: D.O.
Location Address555 W 6TH STMountain Home, AR 72653-3409
Mailing AddressPo Box 707Mountain Home, AR 72654-0707 · (870) 424-7070 · Fax (870) 424-6616
Phone(870) 425-8288
Fax(870) 425-8299
Sole ProprietorNo
Medical School CMSOtherGraduated 2018
Enumeration DateApril 18, 2018
Last NPPES UpdateAugust 13, 20266 updates tracked since enumeration
NPPES CertifiedAugust 13, 2026
✔ NPI 1578050266 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses 4

★ Primary SpecialtyInternal Medicine · Clinical Cardiac ElectrophysiologyAllopathic & Osteopathic Physicians
Taxonomy Code207RC0001X
License✔ Licensed in AR · E18962
Definition
A field of special interest within the subspecialty of cardiovascular disease, specialty of Internal Medicine, which involves intricate technical procedures to evaluate heart rhythms and determine appropriate treatment for them.
Also ListedInternal MedicineTaxonomy 207R00000X · License TL.0007279 (CO), DR.0062850 (CO)
Also ListedHospitalistTaxonomy 208M00000X · License DR.0062850 (CO)
Also ListedStudent in an Organized Health Care Education/Training ProgramTaxonomy 390200000X · License TL.0007279 (CO)
555 W 6TH ST, Mountain Home, AR 72653
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Accepted Insurance

The full list of accepted plans is on the Insurance tab. Issuers include Blue Cross and Blue Shield of Kansas, Inc., Oscar Health Maintenance Organization of Florida, Oscar Insurance Company.Insurance ›

Medicare Participation & PECOS CMS

Medicare enrollment, assignment, and ordering and referring status from the CMS PECOS system.

Medicare Enrollment Status

✔

Enrolled in Medicare and accepts Medicare assignment

Dr. William Spencer Grigg D.o. 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 ID9234476300
PECOS Enrollment IDI20240229001839, I20260413000737
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.

Areas of Expertise CMS Part B claims 2

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.

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.
48 services47 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.
18 services17 patients

Physician Visit Costs CMS claims · ZIP area

Typical Medicare office-visit costs in the 72653 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
$119.36 typical visit price
range $51.36 – $157.74
Typical copayment $29.84 (range $12.84 – $39.43)
Most-billed visit code 99204
Established Patient
$91.63 typical visit price
range $16.16 – $128.77
Typical copayment $22.90 (range $4.04 – $32.19)
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.

Medicare Quality Performance CMS QPP · MIPS

Performance in the CMS Quality Payment Program: the MIPS final score across four weighted categories, and the individual quality measures reported to Medicare.

88.22/100
MIPS Final ScoreMerit-based Incentive Payment System · CMS Quality Payment Program
Scored as part of a group practice
Quality88.96
Promoting Interoperability81
Improvement Activities40

Other Providers at the Same Location NPPES 16

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

DR. OTIS SUMTER WARR IV M.D.
Specialist
555 W 6TH ST
MOUNTAIN HOME, AR 72653
Baxter County (870) 425-8288
JAMES EDWARD CUREINGTON R.N.P.
Nurse Practitioner
555 W 6TH ST
MOUNTAIN HOME, AR 72653
Baxter County (870) 425-8288
DR. TIMOTHY ERIC BOWEN MD
Internal Medicine (Interventional Cardiology)
555 W 6TH ST
MOUNTAIN HOME, AR 72653
Baxter County (870) 425-8288
BAXTER REGIONAL ENTERPRISES, LLC
Specialist
555 W 6TH ST
MOUNTAIN HOME, AR 72653
Baxter County (870) 425-8288
TRAVIS D RICHARDSON, DO, PLLC
Orthopaedic Surgery (Orthopaedic Surgery of the Spine)
555 W 6TH ST
MOUNTAIN HOME, AR 72653
Baxter County (870) 424-4507
LOUIS W ELKINS MD PA
Clinic/Center (Medical Specialty)
555 W 6TH ST
MOUNTAIN HOME, AR 72653
Baxter County (870) 425-3291
JEFFERY D TATE PA-C
Physician Assistant
555 W 6TH ST
MOUNTAIN HOME, AR 72653
Baxter County (870) 425-8288
LEAH DANIELLE FOUNTAIN MSN, NP-C APRN
Nurse Practitioner (Family)
555 W 6TH ST
MOUNTAIN HOME, AR 72653
Baxter County (870) 425-8288

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 William Grigg's NPI number?

The NPI number for William Grigg is 1578050266. It was assigned to this individual provider in the NPPES registry on April 18, 2018.

Where is William Grigg located?

William Grigg practices at 555 W 6th St, Mountain Home, AR 72653. The listed phone number is (870) 425-8288.

What is William Grigg's specialty?

The primary specialty registered for this NPI is Internal Medicine, specializing in Clinical Cardiac Electrophysiology, with taxonomy code 207RC0001X.

Is William Grigg enrolled in Medicare?

Yes. William Grigg 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.

What insurance does William Grigg accept?

Health plans from Blue Cross and Blue Shield of Kansas, Inc., Oscar Health Maintenance Organization of Florida and Oscar Insurance Company list William Grigg as in-network in at least one marketplace plan. Coverage varies by plan and year; verify with the insurer or the provider before a visit.

When was this NPI record last updated?

The NPPES record for William Grigg was last updated on August 13, 2026. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 21 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.