What are the available methods of sample collection?
Saliva can be collected with a straw-like apparatus, into a small plastic tube, or through softly chewing a synthetic fiber roll (Salivette®) for a minute. Additionally there are systems designed to be used specifically for little children and infants, which are also used for collecting saliva samples of animals.
What is to consider during sample collection?
One hour before saliva collection eating a major meal or brushing teeth should be abstained from, since acidic or high sugar foods can compromise assay performance by lowering sample pH and influencing bacterial growth. To minimize these factors, rinse mouth thoroughly with water 10 minutes before sample is collected. After that, drinking should be abstained from as well, since the sample could be diluted and the results distorted. Also abstain from saliva-stimulating substances such a gum, generally. Please document consumption of alcohol, nicotine or prescription/over-the-counter medications within the prior 12 hours. The presence of oral diseases or injuries must be recorded, too. Samples visibly contaminated with blood should be recollected.
How much saliva is needed for analysis?
The minimum volume needed for saliva analysis is 500µl. If there are a multitude of parameters to be determined the volume must rise accordingly. The usual yield from Salivettes® lies between 0.8 -1.4 ml, according to the manufacturer. Using the Passive Drool Method make sure that the collection container is filled adequately. With children and infants saliva collection can prove difficult, which is why we offer our assistance here as well.
What is to consider during labeling of samples?
It is important to record the time and date of specimen collection when samples are obtained due to the diurnal variation in many biomarker levels. This data should be entered into a sample inventory log form, too (please send to the lab electronically as an excel file). If using printable labels please make sure that the labels are temperature-resistant and won't fall off during multiple freeze thaw cycles. For manual labeling please use a permanent marker. The sample number and/or patient ID should be on the side and on the cover top of the tube. Organize the samples consecutively by number in a box or on a rack.
How to store the saliva samples?
After collection the samples should be stored in a cool environment and shipped to the lab as soon as possible. Depending on the biomarker samples are stable for 3-4 days at room temperature. For prolonged periods of storage samples should be frozen at -20°C in a timely fashion.
Advantage of the blue Salivette®?
For saliva collection, the Salivette® is available with different swab options: a plain cotton swab, a cotton swab with citric acid preparation to stimulate salivation, and a synthetic swab specially designed for cortisol determination. Sarstedt developed the Salivette® with the blue cap especially for saliva cortisol measurement. It is characterized by a very high cortisol recovery rate of almost 100% and is particularly suitable if only small amounts of saliva and / or low cortisol levels are expected. For cortisol determination we strongly recommend the blue Salivette®.
What is the Passive Drool Method?
The Passive Drool Method allows for quick and easy collection of saliva. Added advantages: the analytes can be verified reliably, the container can be stored safely at -80°C, but it is not suitable for children under 6 years of age.
For which analytes is the Cortisol -Salivette® best suited for?
Sarstedt developed Salivettes® for the sole purpose of analyzing saliva cortisol. Even though the developer won’t guarantee it, there is a high possibility that it can used for other biomarkers as well. Literary research shows that it can be used for α-amylase and testosterone. The collection being quick and sanitary this is true especially for biomarkers that are subject to hourly fluctuations.
How to collect saliva samples using Salivettes®?
After opening the cap, the synthetic fiber role is removed and placed in the subject’s mouth. After gently moving the jaw for 45 seconds the saliva-saturated fiber role is placed back in the Salivette®. After closing the cap the Salivette® is ready to be stored and shipped.
For which subjects isn’t the Salivette® suited for?
The synthetic fiber role is deemed swallowable, therefore it is not recommended to be used on children younger than 3 years.
What is the DLMO?
The "Dim Light Melatonin Onset" (DLMO) is a time point in which circulating melatonin has risen significantly above the low baseline concentrations present during the day. Melatonin, a sleep-promoting neurohormone, is responsible for the entrainment of circadian rhytm and is produced in response to light/dark stimulation. Melatonin secretion at approximately 2 hours before habitual bedtime, peaks in the middle of the night (2-4 am) and drops to minimal levels during the day with nadir in late afternoon. A misaligned DLMO may indicate delayed sleep phase syndrome (DSPS) or advanced sleep phase disorder (ASPD) and it's relationship to various metabolic conditions, deseases, disorders and genetic and environmental components are of significant interest in current research.
How is the DLMO calculated?
With saliva as a biological sample, researchers can non-invasively monitor melatonin levels without an overnicht sleep clinic stay. This eliminates the rhytm perturbation caused by a clinical sleep center laboratory. Salivary DLMO is determined by measuring salivary Melatonin levels over several time-points prior to and just after habitual sleep time. Determined by a sleep diary for one week prior the habitual sleep time is determined. Saliva samples are taken every half hour or every hour starting three hours before and ending one after the habitual sleep time. It is important that patients need to stay in dim light and no electrical equipment is used at this time (including the bright display of a smart phone).