Allopathic & Osteopathic Physicians / 207UN0903X
Individual · specialization · Medicare specialty 36
207UN0903X In Vivo & In Vitro Nuclear Medicine Physician
207UN0903X is the taxonomy code for In Vivo & In Vitro Nuclear Medicine, a specialization of Nuclear Medicine, in the NUCC group “Allopathic & Osteopathic Physicians”. It is a code for individual providers — the kind used on a Type 1 NPI. Medicare maps it to specialty 36, Physician/Nuclear Medicine, under which 738 practitioners are enrolled.
- 1Taxonomy code 207UN0903X
- 2Level Specialization
- 3Medicare specialty 36 Physician/Nuclear Medicine
- 4Codes in this group 238
Definition
A nuclear medicine physician who specializes in in vivo and in vitro nuclear medicine.
— NUCC Health Care Provider Taxonomy, version 26.1
Where 207UN0903X sits
- Group: Allopathic & Osteopathic Physicians — code 85 of 238 in the group
- Classification: Nuclear Medicine 207U00000X
- Specialization: In Vivo & In Vitro Nuclear Medicine 207UN0903X
Choose 207UN0903X over the general Nuclear Medicine code (207U00000X) when the provider's training or certification is specifically in in vivo & in vitro nuclear medicine; the general code covers the classification as a whole. A provider may report more than one taxonomy code on an NPI but marks one as primary.
Medicare
CMS's taxonomy crosswalk links 207UN0903X to Medicare specialty 36 (Physician/Nuclear Medicine). That specialty — not the taxonomy code itself — is what Medicare enrollment records and uses for payment. 738 practitioners are enrolled under it nationally, and 4 other taxonomy codes map to the same specialty.
Other codes under the same Medicare specialty: 207U00000X Nuclear Medicine Physician; 207UN0901X Nuclear Cardiology Physician; 207UN0902X Nuclear Imaging & Therapy Physician; 2085N0904X Nuclear Radiology Physician.
Related codes
| Code | Nuclear Medicine — other specializations |
|---|---|
| 207U00000X | Nuclear Medicine Physician |
| 207UN0901X | Nuclear Cardiology |
| 207UN0902X | Nuclear Imaging & Therapy |
History of 207UN0903X
NUCC's earliest recorded change to 207UN0903X is from 2010 (definition added, source added).
- 2010-01-01 — definition added, source added
Similar codes in other groups
If 207UN0903X is not quite right, these codes in other groups share a word with it — often the same field practised by a different kind of provider:
- 125Q00000X Oral Medicine Dentistry (Dental Providers)
- 163WC0200X Critical Care Medicine Registered Nurse (Nursing Service Providers)
- 173000000X Legal Medicine (Other Service Providers)
- 1835E0208X Emergency Medicine Pharmacist (Pharmacy Service Providers)
- 1835N0905X Nuclear Pharmacist (Pharmacy Service Providers)
- 364SC0200X Critical Care Medicine Clinical Nurse Specialist (Physician Assistants & Advanced Practice Nursing Providers)
Find providers with 207UN0903X
Using 207UN0903X
The code goes in the taxonomy field of the NPI application in NPPES, and on claims where a payer asks for it — box 24J (shaded) or 33b on the CMS-1500 with the ZZ qualifier, or the PRV segment of an 837 electronic claim. Payers match it against the taxonomy on the NPI record and, for Medicare, against the specialty on the enrollment, so all three should agree. To see which code a provider uses, search their NPI in the lookup.
Sources: NUCC Health Care Provider Taxonomy code set, version 26.1 (CSV); CMS Medicare Provider and Supplier Taxonomy Crosswalk, August 2026; CMS Medicare Fee-For-Service Public Provider Enrollment, extract of 2026-09-29. Checked 2026-10-24. Methodology.