A01

A01, or a01 in lowercase, is an alphanumeric code used across multiple domains to label items, categories, or identifiers. Because it appears in varied systems, its meaning is determined by the context in which it is used. In many applications, A01 is a top-level or early-designation code within a broader classification scheme.

In medical coding, A01 has a well-defined meaning in the ICD-10 classification. It designates typhoid and paratyphoid fevers. The category includes subdivisions such as A01.0 Typhoid fever; A01.1 Paratyphoid fever A; A01.2 Paratyphoid fever B; A01.3 Paratyphoid fever C; and A01.9 Typhoid and paratyphoid fevers, unspecified. This usage provides a standardized way to record and study these infections in health data.

Beyond medicine, A01 is used as a vehicle for labeling in various fields, including transportation, technology, and data management. In transportation networks, A01 may appear as a route or corridor designation within a country’s road system, though the exact meaning varies by jurisdiction. In product labeling or software development, A01 often functions as a model number, build identifier, or initial version tag. In databases and cataloging systems, A01 can serve as a categorical or indexing code to organize items.

Because meanings of a01/A01 are highly context-dependent, it is best interpreted by examining accompanying labels, documentation, or the governing classification scheme. See also A1 and variants like A01.0 or A01.9 for related, more specific uses.