WILLIAM CHARLES O'CALLAHAN JR. MD
NPI 1114964186
Emergency Medicine in Holden, MA

Active since May 31, 2006PECOS EnrolledAccepts Medicare Assignment
5 SHREWSBURY ST STE D, HOLDEN, MA 01520(508) 829-3800(508) 829-3802 Get Directions Write a Review

NPPES record last updated: January 21, 2025. Verified against the NPPES registry weekly; last sync: July 26, 2026.

About William Charles O'callahan Jr. Md NPPES

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

WILLIAM CHARLES O'CALLAHAN JR. MD (NPI 1114964186) is an individual emergency medicine provider in Holden, Massachusetts, licensed in Massachusetts (79001) and active in the NPI registry since May 2006. He is enrolled in Medicare PECOS, is affiliated with Umass Memorial Medical Center/university Campus, and maintains 3 additional practice locations.

NPPES Registry Identity

NPI1114964186
Entity TypeIndividualMale
Primary Taxonomy207P00000X
Provider Legal NameWILLIAM CHARLES O'CALLAHAN JR.Credential: MD
Location Address5 SHREWSBURY ST STE DHolden, MA 01520-1960
Mailing Address5 Shrewsbury St Ste DHolden, MA 01520-1960 · (508) 829-3800 · Fax (508) 829-3802
Fax(508) 829-3802
Sole ProprietorNo
Medical School CMSUniversity Of Massachusetts Medical SchoolGraduated 1990
Enumeration DateMay 31, 2006
Last NPPES UpdateJanuary 21, 2025
NPPES CertifiedJanuary 21, 2025
NPI 1114964186 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses

Primary SpecialtyEmergency MedicineAllopathic & Osteopathic Physicians
Taxonomy Code207P00000X
License Licensed in MA · 79001
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.
5 SHREWSBURY ST STE D, Holden, MA 01520

Secondary Practice Locations 3

Location 12040 Boston Rd Ste 5Wilbraham, MA 01095-1380 · Phone (413) 599-3800 · Fax (413) 279-1900
Location 22040 Boston Road, Ste 5Wilbraham, MA 01095-1380 · Phone (413) 599-3800 · Fax (413) 279-1900
Location 3688 Bliss RoadLongmeadow, MA 01106-1534 · Phone (413) 567-0011 · Fax (413) 567-0013

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

William Charles O'callahan Jr. 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 ID3072692805
PECOS Enrollment IDI20080506000317
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 14

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.

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.
188 services179 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.
179 services173 patients
X-ray of chest, 2 views 71046
A chest X-ray, 2 views, is a quick, painless test that creates pictures of the structures inside your chest, such as your heart, lungs, and blood vessels. Two different angles are used to get a comprehensive view. This helps in diagnosing conditions like pneumonia, heart problems, or lung cancer.
121 services112 patients
New patient office or other outpatient visit with low level of medical decision making, if using time, 30 minutes or more 99203
This service involves an initial office or outpatient visit for a new patient. The healthcare professional will spend 30-44 minutes understanding your health history, current issues, and discussing possible treatment plans. It's a comprehensive evaluation to start your healthcare journey.
88 services88 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.
86 services86 patients
Detection test by multiplex amplified probe technique for severe acute respiratory syndrome coronavirus 2 (sars-cov-2) (covid-19) and influenza virus types a and b 87636
This test detects the presence of SARS-CoV-2 (COVID-19) and Influenza types A and B in your body. It uses a method called the multiplex amplified probe technique to amplify and identify specific virus genes. It helps in early diagnosis and appropriate treatment.
66 services66 patients

Hospital Affiliations CMS Care Compare

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

Umass Memorial Medical Center/University Campus

Acute Care Hospitals · Worcester, MA
4/5 CMS rating
OwnershipVoluntary non-profit - Private
CMS Certification Number220163
Location55 Lake Avenue NorthWorcester, MA 01655 · Worcester County
Emergency services Birthing friendly

Physician Visit Costs CMS claims · ZIP area

Typical Medicare office-visit costs in the 01520 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
$90.70 typical visit price
range $58.86 – $177.36
Typical copayment $22.67 (range $14.71 – $44.34)
Most-billed visit code 99203
Established Patient
$103.48 typical visit price
range $19.11 – $144.84
Typical copayment $25.87 (range $4.77 – $36.21)
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 9

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

Physician Assistant
5 SHREWSBURY ST STE D
HOLDEN, MA 01520
Emergency Medicine
5 SHREWSBURY ST STE D
HOLDEN, MA 01520
Registered Nurse (Administrator)
5 SHREWSBURY ST STE D
HOLDEN, MA 01520
Emergency Medicine
5 SHREWSBURY ST STE D
HOLDEN, MA 01520
Emergency Medicine
5 SHREWSBURY ST STE D
HOLDEN, MA 01520
Emergency Medicine
5 SHREWSBURY ST STE D
HOLDEN, MA 01520
Physician Assistant
5 SHREWSBURY ST STE D
HOLDEN, MA 01520
Clinic/Center (Urgent Care)
5 SHREWSBURY ST STE D
HOLDEN, MA 01520

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 O'callahan's NPI number?

The NPI number for William O'callahan is 1114964186. It was assigned to this individual provider in the NPPES registry on May 31, 2006.

Where is William O'callahan located?

William O'callahan practices at 5 Shrewsbury St Ste D, Holden, MA 01520. The listed phone number is (508) 829-3800.

What is William O'callahan's specialty?

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

Is William O'callahan enrolled in Medicare?

Yes. William O'callahan 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.

Is William O'callahan affiliated with any hospitals?

According to CMS data, William O'callahan is affiliated with Umass Memorial Medical Center/University Campus.

When was this NPI record last updated?

The NPPES record for William O'callahan was last updated on January 21, 2025. NPI Profile syncs with the weekly NPPES data releases published by CMS.