# description
Statement about the degree of clinical certainty that a specific substance was the cause of the manifestation in a reaction event.

# concept[].definition
There is a low level of clinical certainty that the reaction was caused by the identified substance.

# concept[].definition
There is a high level of clinical certainty that the reaction was caused by the identified substance.

# concept[].definition
There is a very high level of clinical certainty that the reaction was due to the identified substance, which may include clinical evidence by testing or rechallenge.

# concept[].definition
The clinical certainty that the reaction was caused by the identified substance is unknown.  It is an explicit assertion that certainty is not known.