subclinical

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Not manifesting characteristic clinical symptoms. Used of a disease or condition.

Pertaining to an illness or condition in its earliest stage; having no symptoms or readily discernible signs.

Not manifesting characteristic clinical symptoms. Used of a disease or condition.

Without clinical manifestations; said of the early stages or a very mild form of a disease, e.g. subclinical disease, infection, parasitism, or when a disease is detectable by clinicopathological tests but not by a clinical examination.

The adjective has one meaning:

Meaning #1: relating to the stage in the development of a disease before the symptoms are observed
  Pertains to noun: clinical (meaning #1)