How Does Saliva Collection & Handling Impact Your Study?Depending on your research question and analytes tested, small variations in collection and handling can have dramatic effects on your data and subsequent interpretation. An upfront understanding of best practices for timing of saliva collection, compatibility of collection method for the analytes to be tested, appropriate sample handling post collection, and storage considerations is ideal to the success of your study.
Saliva Collection Resources
Description: Learn the proper techniques and methods for saliva collection, handling, storage, and shipping with this step-by-step guide. If you’re collecting saliva for biomarker or analyte analysis, we’ve developed this guide to provide you better results with your salivary testing.
Description: Ongoing research is identifying many molecules in saliva that are of interest as biomarkers for various research and diagnostic applications. Limited information exists, however, on the best ways to collect and handle saliva for the analysis of many of these molecules.
Description: The DNA in saliva originates from cells that are shed from the inner linings of the mouth and from white blood cells. These DNA-containing cells are collected, and the DNA is then extracted…
Description: As was noted in the article from our earlier Salivary Bioscience Bulletin devoted to salivary CRP (April 2011), limited information may exist on the best ways to collect and handle saliva for the analysis of many novel biomarkers. In the case of salivary cytokines such as IL-1ß, IL-6, and TNF-a, however...
Description: Studies have reported that some older preschoolers are able to donate saliva samples by spitting or drooling, but researchers have generally found that using some sort of absorbent device is the best way to collect saliva from young children.
Description: Leading salivary bioscience researchers continue to map the biological landscape by including cutting-edge, multisystem measurements in their research. A single saliva sample can provide robust data for multiple analytes, when handled correctly.
Description: The non-invasive nature of saliva testing makes it the method of choice for many types of diagnostic and research applications. Before deciding to use saliva rather than some other body fluid, however, it is necessary to ask the following questions: first, how do the substances being measured enter into saliva, and, secondly, what implications do the various pathways of entry have for the reliability of the measurements?
Saliva Collection Faqs
What are the different saliva collection methods recommended by Salimetrics?
Samples can be collected by passive drool (considered the gold-standard sample), or with the use of a swab. Passive drool collected samples can be used to test any analyte, while saliva collected using swabs will only work for some analytes. We recommend you check our website to determine which analytes have been validated for measuring your analyte of interest. It’s important to be aware that not all swabs are the same. Other manufacturers of oral swabs may not validate their swabs for analytes in saliva, and making the assumption that if it worked for one analyte, it would work for all is erroneous.
The recommendation of collection devices is also dependent on which analytes are to be measured now (and in the future); whether the research participant is an infant, child, adult, elderly, or an animal; and whether the participant is capable of following simple instructions. In general, unstimulated, whole saliva collected by passive drool into high-quality polypropylene vials (cryovials) is the preferred method. The Saliva Collection Aid (SCA) facilitates this process. When passive drool is not a feasible option, then Salimetrics has designed a range of swab based tools to absorb sample based on age of the study participant. Salimetrics swab materials have been extensively tested so that the effects on Salimetrics assays are very well documented.
What is Salimetrics recommendation for passive drool saliva sample storage?
It is critical to maintain the integrity of the saliva sample through proper handling and storage. Once saliva is collected, it should be moved to a refrigerator as soon as possible and within a few hours, be moved to a -20 C non-cycling freezer. Some analytes, e.g., cortisol, are able to withstand room temperature storage for a limited period of time, however, this can be sample specific, and it is best to avoid jeopardizing your study by improperly storing saliva samples at room temperature. It is best-practice to move samples into cold storage immediately after collection. Samples stored for more than 6 months should ideally be moved to a – 80 C freezer.
You can find more detailed information in the Salimetrics Saliva Collection Handbook.
What is Salimetrics recommendation for SalivaBio swab saliva sample storage?
Saliva can be stored in swabs for up to 6 months at -20 C or -80 C. If samples are intended to be stored for longer than this period of time, we suggest that saliva be expressed from the swabs and transferred to cryovials.
Saliva can be expressed from the swab after thawing, by centrifugation at 1500 g for 15 minutes, or by squeezing the swab in the chamber of a 5 cc syringe and expressing the liquid into a cryovial. However, centrifugation is more effective at removing all the liquid from the swab compared to the syringe method. We do not recommend squeezing the swab between fingers to express the liquid out of the swab, but if this has to be done, then gloves should be worn. This method will give the least volume of saliva recovery.
If long term storage is desired and known at the time of sample collection, it is still possible to collect saliva with the swab but we recommend that the liquid from the swab be expressed either by centrifugation or syringe method immediately after collection, and storing the expressed saliva in a cryovial at – 80 C immediately after. This will minimize multiple freeze thaws and ensure integrity of saliva samples.
You can find more detailed information in the Salimetrics Saliva Collection Handbook.
Can saliva samples be shipped by individuals in regular mail?
We always recommend samples be shipped in bioshipper containers made of Styrofoam, and packed on an adequate quantity of dry ice to maintain the cold-chain during the transport period. Generally speaking, samples coming from individuals should be sent to a project coordination site locally, batched and then shipped on dry ice to Salimetrics. Salimetrics SalivaLab only accepts samples that are shipped on dry ice in our Salimetrics Testing Services laboratory.
For home saliva collection, if shipping on dry ice is not possible/practical, then participant’s saliva samples should be frozen and shipped frozen using 3 ice paks in an insulated cooler for a maximum 36 hour delivery. Salimetrics recommends FedEx overnight shipping.
How do I aliquot samples?
To ensure the same concentrations of a certain analyte across all aliquots, it is best to aliquot previously frozen, thawed, and centrifuged saliva samples into multiple tubes. However, this method leads to one extra freeze thaw of the saliva sample, which may have deleterious effects on specific analytes of interest, e.g., CRP. If temperature sensitive analytes are to be tested, we recommend whole saliva be collected in one tube, and aliquots of the whole saliva be made into multiple cryovials. This method will cause some variability in concentrations of an analyte across aliquots but avoids any additional freeze thaw impact on the saliva sample. We do not recommend collecting multiple saliva samples sequentially since the analyte concentrations in each subsequent sample can be different from the previous one.
Do I need to spin saliva sample out of the SalivaBio swabs before freezing and storing them?
You do not have to separate the saliva samples from the Salimetrics swabs before freezing; however, Salimetrics does recommend that the saliva be removed from Salimetrics swabs by centrifugation (or compression) before storage for periods longer than 6 months. Therefore if you plan to store your saliva samples collected with Salimetrics swabs for more than 6 months it would be better to centrifuge before freezing at -40ºC or below, in order to prevent an additional freeze thaw of the sample.
How do I measure flow rate when collecting saliva?
See the Effects of Flow Rate and Mouth Location on Salivary Analytes section of the Saliva Collection Handbook.
Is there an accepted procedure I can use to stimulate saliva flow without interfering with the results?
The key word is “accepted” which is highly subjective. Chewing on unflavored paraffin/wax or rolling a marble around under the tongue has been used by some, but not recommended for flow-dependent analytes. Salimetrics does not recommend using stimulants when collecting saliva.
What are the Salimetrics swabs made of?
SalivaBio swabs (SOS, SCS and SIS) are made of an inert polymer, constructed of food-grade raw material, and processed under food-grade device production conditions. These swabs were validated for use with some Salimetrics salivary kits by Salimetrics. More information and the list of approved analytes can be viewed on our website under Saliva Collection Methods. Each lot of swabs received by Salimetrics undergoes intensive QC testing to ensure minimal lot to lot variability, so there is no impact on data derived from longitudinal studies.
We have a document that we can send upon request: ‘Salimetrics Oral Swab Safety Evaluation Information Sheet’. Salimetrics is not the manufacturer of these swabs and the exact composition is the proprietary property of the manufacturer.
Why do you recommend avoiding alcohol consumption for 12 hours before sample collection?
Salimetrics recommends documenting alcohol consumption as a precaution. Alcohol stimulates saliva flow and is respirated out of the body, thus increased ETOH will be in saliva samples after consumption. High levels of ETOH in saliva samples interfere with the binding of antibodies in enzyme immunoassays. This is really only an issue if the research participant has been drinking heavily within 12 hours or is “hung over”. One or 2 alcoholic beverages within the prior 12 hours is not a problem.
Why is it necessary to have subjects rinse their mouths before taking the samples?
Salimetrics recommends rinsing the mouth with water before collecting saliva samples if food has been consumed. The rinsing removes food particles and minimizes mucous. It is not recommended to rinse the mouth for an awakening sample since no food consumption would have occurred in the night. We recommend waiting a minimum of 10 minutes after rinsing the mouth before sample can be collected. This helps equilibrate the saliva in the mouth, not waiting long enough can cause the collected saliva sample to be very dilute and artificially alter the resulting analyte concentration.
How do I use your saliva collection devices to collect samples for DNA testing?
When collected by passive drool, there are sufficient cells in the pellet that can be used for DNA extraction, while still using the supernatant for analyte testing. The Salimetrics SalivaLab has also developed a proprietary protocol that allows for DNA isolation from the swabs, but this service is only available for samples being sent to Salimetrics.
Information we developed on this topic was published on-line in the following paper:
Nemoda, Z.., Horvat-Gordon, M., Fortunato, C. K., Beltzer, E., Scholl, J. L., Granger, D. A. (2011). Assessing genetic polymorphisms using DNA extracted from cells present in saliva Samples. BMC Medical Research Methodology, 11, 170. PMID 22182470