title: The effect of cotton-based collection methods on eosinophil cationic protein (ECP) concentrations detected in saliva.
abstract: BACKGROUND
  Salivary eosinophil cationic protein (ECP) level has the potential to be an assessment tool for asthma. Its measurement is not well-established and needs standardization. We studied how passive drool (PD) and two commercial devices, Salivette(®) (cotton-based device) and Sorbette(®) (cellulose-cotton-based-device), may affect ECP levels during collection among healthy subjects.
  
  
  METHODS
  Study I (n = 10) involved direct sampling of healthy adult subjects with Salivette(®) and Sorbette(®). Study II (n = 33) involved 'indirect' sampling of previously collected PD by both devices.
  
  
  RESULTS
  In study I, ECP levels were detected in all PD samples but only in three with Sorbette(®) and none with Salivette(®) (collection order: PD, Sorbette(®) and Salivette(®)). We changed the order of collection (Salivette(®), Sorbette(®), PD) and the results were similar (ECP levels detected in all PD samples, three with Sorbette(®) and only one with Salivette(®)). In study II, ECP levels in saliva collected by PD was 12.8 μg/L (median) and using Sorbette(®) and Salivette(®) were < 2.0 μg/L and 3.4 μg/L respectively (p < 0.01). ECP levels in PD correlated with Sorbette(®) (r(s) = 0.79, p < 0.01) and Salivette(®) (r(s) = 0.62, p < 0.01).
  
  
  CONCLUSIONS
  Compared to PD, saliva collected using cotton or cellulose-based collection devices resulted in lower measurable ECP levels.
authors: Department of Community, Occupational and Family Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
authors: Teck Yee
authors: TY
authors: Wong
authors: David
authors: D
authors: Koh
authors: Andrew
authors: A
authors: Wee
authors: Vivian
authors: V
authors: Ng
authors: Yong Tat
authors: YT
authors: Koh
authors: Zhenjie
authors: Z
authors: Sum
authors: Gerald
authors: G
authors: Koh