[Measurement of amylase in saliva collected by salivette]

Saliva is increasingly being used as a specimen for systemic disease as well as for oral health status. Especially, salivary amylase has been studied as an excellent index for psychological stress. Authors evaluated the measurement of salivary amylase activities collected by Salivettes (Sarstedt, Germany).

Saliva specimens were collected from 13 healthy adults between 10:00 and 11:00 a.m. Participants were asked to gently chew tampons of Salivettes for 1 min. Immediately after collection, all specimens were stored frozen. On the day of testing, they were centrifuged after thawing and diluted with distilled water. Amylase was measured by Dimension RxL Max (Dade Behring Inc., USA). We evaluated precision, linearity, and recovery rate of Salivette. Amylase activities between collection of saliva by Salivette and passive drool were compared, and also the changes of amylase by the storage temperature were evaluated.

Intra-run CVs for three levels of amylase were excellent. Between-day CVs and total CVs were good only for mid and high levels. A good linear relationship was found at all diluted levels. Dosing Salivettes with 2 mL, 1.5 mL, and 1 mL yielded sample recovery 85.5+/-2.4%, 82.4+/-1.5%, and 72.2+/-3.1%, respectively and amylase recovery 78.9+/-10.9%, 74.1+/-13.7%, and 37.3+/-26.9%, respectively. Amylase by Salivette and passive drool were correlated well (r=0.757), although they showed a significant difference. Amylase activity was not affected by the storage temperature.

Measurement of salivary amylase using Salivette could be a useful test having good intra-run CVs and linearity. More than 1.5 mL of saliva would be needed to have more than 70% recovery of Salivette.