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RIANA NICOLAYSEN
NPI 1952145351
Nurse Practitioner in Tarzana, CA

Active since June 20, 2024PECOS EnrolledAccepts Medicare Assignment
18646 OXNARD ST, TARZANA, CA 91356(818) 996-1051 Get Directions Write a Review

NPPES record last updated: February 27, 2026. Verified against the NPPES registry weekly; last sync: November 01, 2026.

Record update history: Jan 21, 2026, Jun 20, 2024 (2 updates tracked since 2024).

About Riana Nicolaysen NPPES

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

RIANA NICOLAYSEN (NPI 1952145351) is an individual nurse practitioner in Tarzana, California, licensed in Pennsylvania (SP030566) and active in the NPI registry since June 2024. She is enrolled in Medicare PECOS, maintains a secondary practice location in Philadelphia, and is a graduate of Other (2024).

NPPES Registry Identity

NPI1952145351
Entity TypeIndividualFemale
Primary Taxonomy363L00000X
Provider Legal NameRIANA NICOLAYSEN
Location Address18646 OXNARD STTarzana, CA 91356-1486
Mailing Address18646 Oxnard StTarzana, CA 91356-1486 · (818) 853-1928
Phone(818) 996-1051
Sole ProprietorNo
Medical School CMSOtherGraduated 2024
Enumeration DateJune 20, 2024
Last NPPES UpdateFebruary 27, 20262 updates tracked since enumeration
NPPES CertifiedFebruary 27, 2026
✔ NPI 1952145351 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses

★ Primary SpecialtyNurse PractitionerPhysician Assistants & Advanced Practice Nursing Providers
Taxonomy Code363L00000X
Licenses✔ Licensed in PA · SP030566✔ Licensed in NY · 359127
Definition
(1) A registered nurse provider with a graduate degree in nursing prepared for advanced practice involving independent and interdependent decision making and direct accountability for clinical judgment across the health care continuum or in a certified specialty. (2) A registered nurse who has completed additional training beyond basic nursing education and who provides primary health care services in accordance with state nurse practice laws or statutes. Tasks performed by nurse practitioners vary with practice requirements mandated by geographic, political, economic, and social factors. Nurse practitioner specialists include, but are not limited to, family nurse practitioners, gerontological nurse practitioners, pediatric nurse practitioners, obstetric-gynecologic nurse practitioners, and school nurse practitioners.
18646 OXNARD ST, Tarzana, CA 91356
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Secondary Practice Location 1

Location 1161 Cecil B Moore Ave Apt 204Philadelphia, PA 19122-3243 · Phone (866) 306-2026

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

Riana Nicolaysen 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 ID4688192578
PECOS Enrollment IDI20250514003057, I20260310002497
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 Riana Nicolaysen reassigns Medicare billing to 1 organization. The organization bills Medicare for the services this provider delivers there.

Ophelia Medical Group Fl, P.A.
2,407 mi
Addiction Medicine
161 CECIL B MOORE AVE APT 204
Philadelphia, PA 19122
  • Reassigned Medicare billing, New York and Pennsylvania enrollments
  • Medicare enrollment name: Ophelia Medical Group Fl PA
  • 35 clinicians in this Medicare group
NPI 1588244750 (215) 585-2144

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

Physician Visit Costs CMS claims · ZIP area

Typical Medicare office-visit costs in the 91356 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
$96.36 typical visit price
range $62.96 – $187.60
Typical copayment $24.09 (range $15.74 – $46.90)
Most-billed visit code 99203
Established Patient
$109.96 typical visit price
range $20.84 – $153.61
Typical copayment $27.49 (range $5.21 – $38.40)
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.

DEANNA KATHERINE MALEC RN
Registered Nurse (Case Management)
18646 OXNARD ST
TARZANA, CA 91356
Los Angeles County (818) 996-1051
NICOLE MARIAN JOHNSTONE RADT
Counselor (Addiction (Substance Use Disorder))
18646 OXNARD ST
TARZANA, CA 91356
Los Angeles County (818) 654-3950
ARTURO VARGAS
Peer Specialist
18646 OXNARD ST
TARZANA, CA 91356
Los Angeles County (818) 996-1051
DAVID JEROME FISCHER
Peer Specialist
18646 OXNARD ST
TARZANA, CA 91356
Los Angeles County (818) 996-1051
GREGORY PAUL WALSH
Counselor (Addiction (Substance Use Disorder))
18646 OXNARD ST
TARZANA, CA 91356
Los Angeles County (818) 996-1051
DAVID HEISERMAN
Counselor (Addiction (Substance Use Disorder))
18646 OXNARD ST
TARZANA, CA 91356
Los Angeles County (747) 224-0384
JOSHUA KELLY
Student in an Organized Health Care Education/Training Program
18646 OXNARD ST
TARZANA, CA 91356
Los Angeles County (859) 779-2349
SHAWNA ROSE GLUCK
Peer Specialist
18646 OXNARD ST
TARZANA, CA 91356
Los Angeles County (181) 899-6105

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 Riana Nicolaysen's NPI number?

The NPI number for Riana Nicolaysen is 1952145351. It was assigned to this individual provider in the NPPES registry on June 20, 2024.

Where is Riana Nicolaysen located?

Riana Nicolaysen practices at 18646 Oxnard St, Tarzana, CA 91356. The listed phone number is (818) 996-1051.

What is Riana Nicolaysen's specialty?

The primary specialty registered for this NPI is Nurse Practitioner with taxonomy code 363L00000X.

Is Riana Nicolaysen enrolled in Medicare?

Yes. Riana Nicolaysen 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 Riana Nicolaysen's services?

According to the CMS Revalidation Reassignment List (October 2026 release), Riana Nicolaysen reassigns Medicare benefits to Ophelia Medical Group Fl, P.A. (Philadelphia, PA). 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 Riana Nicolaysen'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 Riana Nicolaysen was last updated on February 27, 2026. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 8 months 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.