FAQs (frequently asked questions)



Q: Which method is recommended for saliva collection?

The Salivette
The Salivette

A: There are a number of ways to sample saliva. One of the easiest is to use a device called the "Salivette". The Salivette is manufactured and sold by Sarstedt (www.sarstedt.com). Subjects should be instructed to gently chew on the cotton roll to stimulate saliva flow rate. With this it usually takes less than a minute to obtain a saliva sample of 0.5-1 ml volume. Sarstedt currently offers three different versions of the Salivette. We recommend to use the blue-capped "Cortisol Salivette".


Caution: DO NOT USE THE CITRIC ACID STIMULATED SALIVETTES (green caps)!! Saliva samples obtained with these devices have a low pH which interfers with most immunoassays known. It may produce false high steroid assay results.





Q: Which medications or food ingredients will interfer with salivary cortisol?

A: The level of salivary cortisol is influenced by drugs such as prednisone, dexamethasone and other steroids administered orally or i.v. While prednisone usually crossreacts with the antiserum used for assaying cortisol (leading to false high values), dexamethasone will significantly suppress the HPA axis (resulting in low cortisol levels). Furthermore, if the subjects deliver saliva samples with a low pH (e.g., following stimulation of saliva flow by crystals of vitamin C, consumption of fruit juices immediately before sampling etc.) most immunoassay will produce false high cortisol levels.



Q: Do I have to store the saliva samples in the refrigerator or freezer immediately?

A: No. Studies have shown that salivary cortisol is stable at room temperature for at least 4-7 days. Note however, that sampling devices like the Salivette may begin to mold when soaked with saliva and stored at ambient temperature for prolonged periods of time. This produces a bad smelling sample. It does not appear to affect the cortisol levels, though, but it sure affects the mood of the technicians assaying your samples! So whenever possible, saliva samples should be stored at -20 degrees Celsius or lower.



Q: Do I have to use dry ice if I send my samples to the laboratory?

A: No, if you want to have cortisol or alpha amylase analyzed from your saliva samples. Those samples can be transported without dry ice to us if the shipment takes less than 5 days.  However, if you expect that the delivery takes longer, or if you want other analytes to be measured, we recommend to use dry ice. Use dry ice also if you are shipping serum/plasma or urine samples. No refrigeration at all is needed for the shipment of hair samples.



Q: Does repeated freezing and thawing of the saliva samples affect the cortisol levels?

A: No (at least up to four freeze/thaw cycles).



Q: What are the assay costs for your services?

A: The price differs between analytes and analytical method requested. As a rule of thumb, expect to pay between 5.00 and 8.00 USD for the immunoassay per hormone assayed from saliva, blood, or urine. The analysis by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) is more expensive (from 28.00 USD). However, here you will receive results for up to seven steroid hormones from a single sample.