Evaluation of saliva collection devices for the analysis of proteins Eleni Topkas a , Patricia Keith a , Goce Dimeski b, c , Justin Cooper-White a, d , Chamindie Punyadeera a, d, ⁎ a The Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Australia b Chemical Pathology, Princes Alexandra Hospital, Pathology Queensland, The University of Queensland, Australia c School of Medicine, Southside Clinical School, The University of Queensland, Australia d The School of Chemical Engineering and the University of Queensland, Australia abstract article info Article history: Received 14 December 2011 Received in revised form 30 January 2012 Accepted 20 February 2012 Available online 3 March 2012 Keywords: Saliva Diagnostic Proteins Saliva collection devices and methods Reference intervals Background: Human saliva mirrors the body's health and can be collected non-invasively, does not require specialized skills and is suitable for large population based screening programs. The aims were twofold: to evaluate the suitability of commercially available saliva collection devices for quantifying proteins present in saliva and to provide levels for C-reactive protein (CRP), myoglobin, and immunoglobin E (IgE) in saliva of healthy individuals as a baseline for future studies. Methods: Saliva was collected from healthy volunteers (n =17, ages 18–33 years). The following collection methods were evaluated: drool; Salimetrics® Oral Swab (SOS); Salivette® Cotton and Synthetic (Sarstedt) and Greiner Bio-One Saliva Collection System (GBO SCS®). We used AlphaLISA® assays to measure CRP, IgE and myoglobin levels in human saliva. Results: Significant (p b 0.05) differences in the salivary flow rates were observed based on the method of col- lection, i.e. salivary flow rates were significantly lower (p b 0.05) in unstimulated saliva (i.e. drool and SOS), when compared with mechanically stimulated methods (p b 0.05) (Salivette® Cotton and Synthetic) and acid stimulated method (p b 0.05) (SCS®). Saliva collected using SOS yielded significantly (p b 0.05) lower concentrations of myoglobin and CRP, whilst, saliva collected using the Salivette® Cotton and Synthetic swab yielded significantly (p b 0.05) lower myoglobin and IgE concentrations respectively. Conclusions: The results demonstrated significantly relevant differences in analyte levels based on the collec- tion method. Significant differences in the salivary flow rates were also observed depending on the saliva col- lection method. The data provide preliminary baseline values for salivary CRP, myoglobin, and IgE levels in healthy participants and based on the collection method. © 2012 Elsevier B.V. All rights reserved. 1. Introduction Saliva is an important biological fluid with many functions in the oral cavity including maintaining oral homeostasis [1]. Saliva contains a wide spectrum of biomolecules that are either synthesized in situ or transported from the blood capillaries into salivary acinar cells [2]. Not only can human saliva provide important information about the oral cavity, it also harbors a wealth of information that is derived from tissues/organs in the body. Such information can be used to as- sess and monitor health, well-being and disease status or alternative- ly be used to determine response to drug treatments [3–7]. A recent study by Bandhakavi et al. has identified 2340 proteins in human saliva and approximately 20% of these proteins are also found in plasma [8]. This highlights the importance and potential of saliva as a biological fluid and warrants more comprehensive evaluation as a diagnostic medium. There has been increasing interest in saliva diag- nostics due to its non-invasive nature and ease of collection [3–5,9–13]. Much of the literature on the use of saliva research focus- es on developing technologies for the detection of biomolecules [5,11–15]. However, important consideration must also be given to the effects of different saliva collection and processing methods and their influence on the accuracy of results as well as reference interval or cut off limits [8–13,15,16]. Currently, saliva assays are routinely used to determine, disease such as HIV [17], illicit drug use [16,17], cortisol levels for diagnosing Cushing's syndrome [18] and to measure many other hormones [19–21]. Saliva has numerous advantages over blood or urine as a di- agnostic fluid: a) the non-invasive nature of sample collection and simple, safe, painless, and cost-effective; b) unskilled people can col- lect saliva samples at multiple time points; c) the total protein con- centration is approximately a quarter of what is present in plasma which makes it easier to investigate low abundant proteins [5,6,22]. Human saliva can be collected either under resting conditions or stimulated conditions, such as mechanical stimulation via chewing Clinica Chimica Acta 413 (2012) 1066–1070 ⁎ Corresponding author at: Saliva Research Group Tissue Engineering and Microfluidic Laboratory, the Australian Institute for Bioengineering and Nanotechnology, The Univer- sity of Queensland, Old Cooper Road, St. Lucia, 4072, Queensland, Australia. Tel.: +61 7 3346 3891; fax: +61 7 3346 3973. E-mail address: c.punyadeera@uq.edu.au (C. Punyadeera). 0009-8981/$ – see front matter © 2012 Elsevier B.V. All rights reserved. doi:10.1016/j.cca.2012.02.020 Contents lists available at SciVerse ScienceDirect Clinica Chimica Acta journal homepage: www.elsevier.com/locate/clinchim