Some types are capable of establishing persistent asymptomatic infections in tonsils, adenoids, and intestines of infected hosts, and shedding can occur for months or years.
Many individuals have meningiomas but remain asymptomatic (no symptoms) for their entire life, so the meningiomas are not discovered until after an autopsy.
Lingual thyroid may be asymptomatic, or give symptoms such as dysphagia (difficulty swallowing), dysphonia (difficulty talking) and dyspnea (difficulty breathing).
There is a significant overlap of drug concentrations in body fluids within the possible spectrum of physiological reactions ranging from asymptomatic to comatose.