"A factor that renders the administration of a drug or the carrying out of a medical procedure inadvisable." - Stedman's Medical Dictionary. Note that because almost all Contra-Indications are Health Concerns, for example, "Allergy to Eggs", "Allergy to Aluminum", "Current fever with moderate-to-severe illness", the Contra-Indication is modeled as relationship to Health Concern, and the Contra-Indication code may be derived from the Health Concern code. This having been said, there are some members of the Contra-Indication Value Set that are too general to point to a single Health Concern, even though they might still be derivable from the Health Concern list. Examples include "Chronic disease (disorder)", and "Immunodeficiency due to any cause, including HIV (hematologic and solid tumors, congenital immunodeficiency, long-term immunosuppressive therapy, including steroids)".

This class is a record of an assertion by the patient, the patient guardian, or someone else in authority that the medication should not be administered. Examples include a parent refusing an immunization for their child based on religious beliefs.

"Information about the actual consumption of medication by a patient. While this is generally only relevant for hospital/institutional systems which track individual administrations, it could also be used in ambulatory care e.g. home-health environments which capture administrations such as insulin injections and which use messaging to communicate the information back to a central source; recording immunizations." (HL7 Version 3).