Individual provider

Elizabeth Nielsen, MD

Pulmonary Disease Physician Internal Medicine Physician Critical Care Medicine (Internal Medicine) Physician Medicare enrolled

Elizabeth Nielsen, MD is a Pulmonary Disease Physician in Waukesha, WI, registered under NPI 1861842007. This provider registers 3 separate taxonomy codes, which usually means they practise across more than one recognised specialty. NPPES records them as a sole proprietor, meaning the practice is not incorporated as a separate legal entity.

Getting there

The practice address on file is 725 AMERICAN AVE, Waukesha, WI 53188. We have not yet mapped what surrounds this office — parking, transit, and nearby pharmacies are added as our data collection reaches each location.

725 AMERICAN AVE, Waukesha, WI 53188 Open in Google Maps →

Credentials and Medicare

State licence
LicenceStateSpecialty
76831 WI Pulmonary Disease Physician primary
125.068567 IL Internal Medicine Physician
01089069A IN Internal Medicine Physician
036147784 IL Critical Care Medicine (Internal…
76831 WI Critical Care Medicine (Internal…
036147784 IL Pulmonary Disease Physician

Licences are recorded in 3 states: WI, IL, IN. Providers licensed in several states often practise near a state border or deliver telehealth across state lines.

Medicare (PECOS)
Status
Approved
Provider type
Practitioner - Internal Medicine
PAC ID
7618262338

Enrolled in Medicare 3 times, across 3 states:

StateEnrollment IDProvider type
Illinois I20230119000734 Practitioner - Internal Medicine
Indiana I20230124002834 Practitioner - Internal Medicine
Wisconsin I20230727000954 Practitioner - Pulmonary Disease

Medicare enrolment is recorded as approved under the provider type Practitioner - Internal Medicine. There are 3 separate enrolment records across 3 states (IL, IN, WI). Multiple enrolments usually mean the provider bills Medicare from more than one practice location, or has kept an earlier enrolment after moving. Each record carries its own enrolment ID, listed above. Being enrolled means the provider can bill Medicare; it does not tell you whether they are currently accepting new Medicare patients. Call the office to confirm.

Licensed in 3 states

This provider holds licences in 3 states: Illinois, Indiana and Wisconsin. The practice address on file is in Waukesha, WI, but a licence in another state usually means they see patients there too — either at a second location or by telehealth. If the address above is far from you, it is worth calling to ask whether they practise closer to where you live.

IL Illinois
Licence
125.068567
Specialty
Internal Medicine Physician
Verify with the IL board →
IN Indiana
Licence
01089069A
Specialty
Internal Medicine Physician
Verify with the IN board →
WI Wisconsin practice address
Licence
76831
Specialty
Pulmonary Disease Physician
Verify with the WI board →

Licence numbers are self-reported to NPPES at registration. They do not confirm a licence is currently active, in good standing, or valid for the specialty shown — only the state board can tell you that, which is why we link to each one.

What Pulmonary Disease covers

An internist who treats diseases of the lungs and airways. The pulmonologist diagnoses and treats cancer, pneumonia, pleurisy, asthma, occupational and environmental diseases, bronchitis, sleep disorders, emphysema and other complex disorders of the lungs. NUCC Health Care Provider Taxonomy, code 207RP1001X
Allopathic & Osteopathic Physicians Internal Medicine Pulmonary Disease

All registered taxonomy codes

This provider registers 6 taxonomy codes. The primary code is what appears on most claims; the others record additional recognised specialties.

CodeSpecialtyLicenceState
207RP1001X Pulmonary Disease Physician Pulmonary Disease 76831 WI primary
207R00000X Internal Medicine Physician 125.068567 IL
207R00000X Internal Medicine Physician 01089069A IN
207RC0200X Critical Care Medicine (Internal Medicine) Physician Critical Care Medicine 036147784 IL
207RC0200X Critical Care Medicine (Internal Medicine) Physician Critical Care Medicine 76831 WI
207RP1001X Pulmonary Disease Physician Pulmonary Disease 036147784 IL

The taxonomy records how the provider classifies their own practice. It does not confirm which conditions they currently treat, whether they are accepting new patients, or which insurance they take — call the office for that.

Full NPPES record

An NPI-1 identifies a single person. It stays with the clinician for life, even if they move practice or change state, which is why the address on file can lag behind where they actually work today.

NPI1861842007 valid check digit
Entity typeIndividual (NPI-1)
Enumeration dateJun 19, 2016
Last updatedSep 21, 2023
StatusActive
Sole proprietorYes
CredentialMD
Practice address 725 AMERICAN AVE
Waukesha, WI 53188
(262) 928-3000
Fax (262) 953-8814
Mailing address 725 AMERICAN AVENUE
Waukesha, WI 53188
This record was updated on Sep 21, 2023, which is recent enough that the contact details are likely still accurate.

Number check

1861842007 passes the NPI check digit test The final digit 7 matches the value computed from the first nine digits, so this is a well-formed NPI.
How the check works, step by step

Every NPI carries a Luhn check digit — the same scheme used on credit cards. CMS prefixes the number with 80840 before computing it, which marks it as a US health identifier.

Digit 8 0 8 4 0 1 8 6 1 8 4 2 0 0
Doubled? ×2 ×2 ×2 ×2 ×2 ×2 ×2
Value 8 0 8 8 0 2 8 3 1 7 4 4 0 0

Sum = 53 · next multiple of 10 = 60 · check digit = 7 · actual last digit = 7

A valid check digit only means the number is well-formed. It does not mean the provider is licensed, active, or in good standing — those are separate questions answered by the sections above.

Common questions

What is NPI number 1861842007?
NPI 1861842007 is the National Provider Identifier assigned to Elizabeth Nielsen, MD in Waukesha, WI. It is a 10-digit number issued by the Centers for Medicare & Medicaid Services and used on claims, referrals, and prescriptions to identify the provider.
What does Pulmonary Disease cover?
An internist who treats diseases of the lungs and airways. The pulmonologist diagnoses and treats cancer, pneumonia, pleurisy, asthma, occupational and environmental diseases, bronchitis, sleep disorders, emphysema and other complex disorders of the lungs.
How do I contact Elizabeth Nielsen, MD?
The phone number on file with NPPES is (262) 928-3000, last updated Sep 21, 2023. Because NPPES is only updated when a provider files a change, call ahead to confirm the number and the current practice address before visiting.
Does Elizabeth Nielsen, MD accept Medicare?
This NPI has an approved Medicare enrolment in PECOS, which means the provider is enrolled to bill Medicare. Enrolment does not guarantee they are accepting new Medicare patients — verify directly with the office.
Is NPI 1861842007 a valid number?
Yes. 1861842007 passes the Luhn check digit validation that CMS uses for NPI numbers, and it resolves to an active record in the registry.
How to use this page. Everything here comes from public federal records. Tips Health does not verify quality of care, confirm that a licence is currently active, or check malpractice history, and accepts no fees for placement. A listing is not a recommendation. Verify independently before seeking care.