Mark Nielsen, M.D.
Mark Nielsen, M.D. is a Thoracic Surgery (Cardiothoracic Vascular Surgery) Physician in Sioux City, IA, registered under NPI 1922056894. 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 4630 SINGING HILLS BLVD SUITE A, Sioux City, IA 51106. We have not yet mapped what surrounds this office — parking, transit, and nearby pharmacies are added as our data collection reaches each location.
Credentials and Medicare
| Licence | State | Specialty |
|---|---|---|
| 036115004 | IA | Thoracic Surgery (Cardiothoracic Vascular… primary |
This provider holds licence 036115004 issued in IA. A licence number in NPPES reflects what was filed at registration — it does not confirm the licence is still active today.
This NPI does not appear in the PECOS Medicare enrolment file. Providers who do not bill Medicare — or who bill only through a group's enrolment — will not appear here. It is not a sign of any problem with the registration.
What Thoracic Surgery (Cardiothoracic Vascular Surgery) covers
A thoracic surgeon provides the operative, perioperative and critical care of patients with pathologic conditions within the chest. Included is the surgical care of coronary artery disease, cancers of the lung, esophagus and chest wall, abnormalities of the trachea, abnormalities of the great vessels and heart valves, congenital anomalies, tumors of the mediastinum and diseases of the diaphragm. The management of the airway and injuries of the chest is within the scope of the specialty. NUCC Health Care Provider Taxonomy, code 208G00000X
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.
| NPI | 1922056894 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | May 4, 2006 |
| Last updated | Dec 7, 2009 |
| Status | Active |
| Sole proprietor | Yes |
| Credential | M.D. |
| Practice address |
4630 SINGING HILLS BLVD SUITE A Sioux City, IA 51106 (712) 271-8346 Fax (712) 271-8347 |
Number check
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 | 9 | 2 | 2 | 0 | 5 | 6 | 8 | 9 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 9 | 4 | 2 | 0 | 5 | 3 | 8 | 9 |
Sum = 66 · next multiple of 10 = 70 · check digit = 4 · actual last digit = 4
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.