Laboratories / 291U00000X
Non-Individual · classification · Medicare specialty 69
291U00000X Clinical Medical Laboratory
291U00000X is the taxonomy code for Clinical Medical Laboratory, in the NUCC group “Laboratories”. It is a code for organizations — the kind used on a Type 2 NPI. Medicare maps it to specialty 69, Clinical Laboratory, under which 0 practitioners are enrolled, and to 1 other specialty listed below.
- 1Taxonomy code 291U00000X
- 2Level Classification
- 3Medicare specialty 69 Clinical Laboratory
- 4Codes in this group 4
Definition
(1) A clinical laboratory is a facility for the biological, microbiological, serological, chemical, immunohematological, hematological, biophysical, cytological, pathological, or other examination of materials derived from the human body for the purpose of providing information for the diagnosis, prevention, or treatment of any disease or impairment of, human beings. These examinations also include procedures to determine, measure, or otherwise describe the presence or absence of various substances or organisms in the body. Facilities only collecting or preparing specimens (or both) or only serving as a mailing service and not performing testing are not considered clinical laboratories. (2) Any facility that examines materials from the human body for purposes of providing information for the diagnosis, prevention, or treatment of any disease or impairment of, or the assessment of, the health of human beings. Typical divisions of a clinical laboratory include hematology, cytology, bacteriology, histology, biochemistry, medical toxicology, and serology.
— NUCC Health Care Provider Taxonomy, version 26.1
Where 291U00000X sits
- Group: Laboratories — code 1 of 4 in the group
- Classification: Clinical Medical Laboratory 291U00000X
Clinical Medical Laboratory has no specializations, so 291U00000X is the only code for it. A provider may report more than one taxonomy code on an NPI but marks one as primary.
Medicare
CMS's taxonomy crosswalk links 291U00000X to Medicare specialty 69 (Clinical Laboratory) and Medicare specialty B4[14] (Rural Health Clinic). That specialty — not the taxonomy code itself — is what Medicare enrollment records and uses for payment. 0 practitioners are enrolled under it nationally.
Related codes
No other codes share the classification Clinical Medical Laboratory. The rest of Laboratories is on the group page.
History of 291U00000X
NUCC's notes record no dated changes for 291U00000X. The code set is republished every January and July, when codes are added, retitled or marked inactive; this page reflects version 26.1, so check the NUCC site if you are reading it after the next release.
Similar codes in other groups
If 291U00000X 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:
- 207KI0005X Clinical & Laboratory Immunology (Allergy & Immunology) Physician (Allopathic & Osteopathic Physicians)
- 208U00000X Clinical Pharmacology Physician (Allopathic & Osteopathic Physicians)
- 207NI0002X Clinical & Laboratory Dermatological Immunology Physician (Allopathic & Osteopathic Physicians)
- 207PE0004X Emergency Medical Services (Emergency Medicine) Physician (Allopathic & Osteopathic Physicians)
- 207PT0002X Medical Toxicology (Emergency Medicine) Physician (Allopathic & Osteopathic Physicians)
- 202C00000X Independent Medical Examiner Physician (Allopathic & Osteopathic Physicians)
Find providers with 291U00000X
Using 291U00000X
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.