MRS. SERENE WILLIAMS-KASILI FNP-BC
NPI 1144696675
Nurse Practitioner - Family in Chelmsford, MA

Active since August 19, 2015PECOS EnrolledAccepts Medicare Assignment
35 VILLAGE SQUARE, CHELMSFORD, MA 01824(978) 250-9495(978) 250-3989 Get Directions Write a Review

NPPES record last updated: August 19, 2015. Verified against the NPPES registry weekly; last sync: October 18, 2026.

About Mrs. Serene Williams-kasili Fnp-bc NPPES

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

MRS. SERENE WILLIAMS-KASILI FNP-BC (NPI 1144696675) is an individual family provider in Chelmsford, Massachusetts, licensed in Massachusetts (RN276978) and active in the NPI registry since August 2015. She is enrolled in Medicare PECOS, is affiliated with Newton-wellesley Hospital, and is a graduate of Other (2015).

NPPES Registry Identity

NPI1144696675
Entity TypeIndividualFemale
Primary Taxonomy363LF0000X
Provider Legal NameMRS. SERENE WILLIAMS-KASILICredential: FNP-BC
Location Address35 VILLAGE SQUAREChelmsford, MA 01824
Mailing Address35 Village SquareChelmsford, MA 01824 · (978) 250-9495 · Fax (978) 250-3989
Fax(978) 250-3989
Sole ProprietorNo
Medical School CMSOtherGraduated 2015
Enumeration DateAugust 19, 2015
✔ NPI 1144696675 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses

★ Primary SpecialtyNurse Practitioner · FamilyPhysician Assistants & Advanced Practice Nursing Providers
Taxonomy Code363LF0000X
License✔ Licensed in MA · RN276978
35 VILLAGE SQUARE, Chelmsford, MA 01824

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

Mrs. Serene Williams-kasili Fnp-bc 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 ID8325308596
PECOS Enrollment IDI20180207003005
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 Reassignment

Medicare enrollment records show Serene Williams-kasili reassigns Medicare billing to 1 organization. The organization bills Medicare for the services this provider delivers there.

Internal Medicine
228 BILLERICA RD
Chelmsford, MA 01824
  • Reassigned Medicare billing, Massachusetts enrollment
  • 1,317 clinicians in this Medicare group

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 23

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.
124 services117 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.
100 services97 patients
Insertion of needle into vein for collection of blood sample 36415
This procedure involves inserting a small needle into a vein, typically in your arm, to collect a blood sample. It's a quick and simple process to help diagnose or monitor health conditions. You may feel a small prick, but discomfort is minimal.
92 services74 patients
Injection, zoledronic acid, 1 mg J3489
Zoledronic acid is a medication given via injection to strengthen bones. It's often used in patients with osteoporosis or certain types of cancer. The injection helps reduce the risk of fractures and other bone complications.
60 services12 patients
Detection test by immunoassay with direct visual observation for influenza virus 87804
This is a test that identifies the influenza virus in your body. It works by using an immunoassay, a method that detects the presence of the virus through an immune response. The results are directly observable, making it a quick and efficient way to diagnose flu.
54 services27 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.
51 services46 patients

Hospital Affiliations CMS Care Compare

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

Newton-Wellesley Hospital

Acute Care Hospitals · Newton, MA
5/5 CMS rating
OwnershipVoluntary non-profit - Private
CMS Certification Number220101
Location2014 Washington StreetNewton, MA 02462 · Middlesex County
Emergency services Birthing friendly

Physician Visit Costs CMS claims · ZIP area

Typical Medicare office-visit costs in the 01824 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
$97.64 typical visit price
range $63.72 – $189.86
Typical copayment $24.41 (range $15.93 – $47.46)
Most-billed visit code 99203
Established Patient
$111.18 typical visit price
range $21.07 – $155.29
Typical copayment $27.79 (range $5.26 – $38.82)
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.

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 Serene Williams-kasili's NPI number?

The NPI number for Serene Williams-kasili is 1144696675. It was assigned to this individual provider in the NPPES registry on August 19, 2015.

Where is Serene Williams-kasili located?

Serene Williams-kasili practices at 35 Village Square, Chelmsford, MA 01824. The listed phone number is (978) 250-9495.

What is Serene Williams-kasili's specialty?

The primary specialty registered for this NPI is Nurse Practitioner, specializing in Family, with taxonomy code 363LF0000X.

Is Serene Williams-kasili enrolled in Medicare?

Yes. Serene Williams-kasili 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 organization bills Medicare for Serene Williams-kasili's services?

According to the CMS Revalidation Reassignment List (October 2026 release), Serene Williams-kasili reassigns Medicare benefits to Atrius Health, Inc. (Chelmsford, MA). The 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 Serene Williams-kasili's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.

Is Serene Williams-kasili affiliated with any hospitals?

According to CMS data, Serene Williams-kasili is affiliated with Newton-Wellesley Hospital.

When was this NPI record last updated?

The NPPES record for Serene Williams-kasili was last updated on August 19, 2015. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 11 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.