The method of introducing the therapeutic material into or onto the subject.

Discussion: Route, site of administration (administrationSiteCode) and the device used in administration are closely related. All three (if present) must be closely coordinated and in agreement. In some cases, the coding system used to specify one may pre-coordinate one or more of the others.

When the medication is delivered to an environmental site, or a location, the route code indicates a site on its "body".

Examples: per os (PO), sublingual (SL), rectal (PR), per inhalationem (IH), ophtalmic (OP), nasal (NS), otic (OT), vaginal (VG), intra-dermal (ID), subcutaneous (SC), intra-venous (IV), and intra-cardial (IC)