Saliva Collection Methods

People often ask us the best method to use when sampling saliva for their studies. There are quite a few considerations that may affect your choice of whether to use passive drool collection or SalivaBio swabs, so to help you with your decision we’ve made the below table, which shows some advantages and disadvantages of each method:

	Passive Drool	SalivaBio Swab Collection
Assay Inteference	Does not interfere with ELISA-based assays if using suitable collection devices	Can interfere with ELISA-based assays for certain analytes – see overleaf
Monitoring collected volume	The volume of collected saliva can easily be visually confirmed – ideal for flow-rate measurement	The volume of saliva collected can only be confirmed accurately by weighing before and after sampling. To check you have enough saliva to test you can centrifuge or syringe
Mouth location	Differences in analyte concentration at different mouth locations are not a consideration for passive drool, but you cannot use it to collect from specific mouth locations	Mouth location must be specified & controlled for swab collection, but you can also use swabs to collect from specific mouth locations
Intended Usage	Cannot be used in animals or infants, difficult to use in children younger than 6 years old	SalivaBio Infant Swabs (SCS) and SalivaBio Childrens’ Swabs can be used by researchers to collect saliva from infants and children. SCS are popular to use when collecting from animals
Sample quality	Sample is more viscous with more particulate, making handling more difficult & potentially giving higher %CVs in testing. A greater volume is needed for accurate pipetting.	Sample is less viscous with less particulate, giving easier handling of lower volumes & potentially lower %CVs in testing.
Flow rate effects	Passive flow – sampling can take longer, putting more burden on participants. It is much easier to measure flow rate using passive drool.	Stimulated flow – Sampling takes less time, but when measuring flow rate you must be careful not to fully saturate swabs, and can only monitor collected volume by weight.
Participant burden	Can be seen as unpleasant by participants. The SalivaBio Saliva Collection Aid (SCA) has been designed to help overcome this issue and increase compliance.	More convenient, lower burden
Storage	Cryovials can be conveniently stored at -20°C/ -80°C without volume loss by evaporation	Swab storage tubes must be sealed with parafilm and stored in an air-tight container if stored for longer than 3 months at -20°C/ -80°C

 

Cotton-based swabs have been shown to interfere with the measurement of several analytes, leading to inaccurate results. The SalivaBio swabs supplied by Salimetrics overcome these problems and are validated for use with many of our kits. SalivaBio swabs are therefore a superior method to use for many analytes, but are unfortunately still not suitable for use with all analytes. A table showing which collection methods are recommended for each analyte is shown below:

 

Analyte	Passive drool	SalivaBio Swab
17a-OH-progesterone
Alpha-Amylase
Androstenedione
C-Reactive Protein
Cortisol
Cotinine
DHEA
DHEA-S
Estradiol (E2)
Estriol (E3)
Estrone (E1)
Interleukin-6
Interleukin-1 Beta
Melatonin
Progesterone
Secretory Immunoglobulin A
Testosterone
Transferrin/ Blood Contamination

 

There is lots more to know about sampling saliva for different analytes. For more information, please contact us for an information pack at: technical@stratech.co.uk