The potential of oral fluid in drug monitoring: an update

Oral fluid, more commonly known as saliva, may be used today alternatively to blood/plasma (which have been used for decades in laboratory diagnostics procedures), for instance, in therapeutic drug monitoring and determination of drugs in several contexts [1]. This sample was first used in 1970 for therapeutic drug monitoring and, since then, its use has been increasing, in part due to the development of more sensitive and reliable technology and to the several advantages it presents in a number of settings. Water is its main component (99%) and this makes laboratory manipulation and pretreatment procedures simpler compared with other biological samples [2].