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® (rs = 0.79, p < 0.01) and Salivette® (rs = 0.62, p < 0.01). Conclusion: Compared to PD, saliva collected using cotton or cellulose-based collection devices resulted in lower measurable ECP levels. © 2008 Wong et al, publisher and licensee Dove Medical Press Ltd.