The usage method of saliva DNA collection cards is relatively simple. The following are the general operation steps:

I. Preparation before Collection

1. Inspect the Collection Card
   • Before using the saliva DNA collection card, first check whether the collection card is intact without signs of damage or moisture. Ensure that the packaging of the collection card is in good condition, as a damaged package may contaminate the collection card and affect the quality of the DNA sample.
   • Check the instruction information on the collection card, including the expiration date, storage conditions, and other important details. Generally, the collection card should be used within the expiration date and stored according to the specified storage conditions (such as a dry and cool environment).
2. Prepare Collection Tools
   • Usually, a clean collection container, such as a sterile plastic cup, is needed to collect saliva. Make sure the container is clean and free of residual chemicals or other impurities to prevent contamination of the saliva sample.
   • Some collection cards may also require supporting collection tools such as swabs or pipettes to assist in collecting saliva. Ensure that these tools have been disinfected.

II. Saliva Collection

1. Stimulate Saliva Secretion
   • Before collecting saliva, you can stimulate saliva secretion through some simple methods to obtain an adequate sample volume. For example, you can chew sugar – free gum, suck on sugar – free candies, or imagine eating sour foods. It is generally recommended to stimulate saliva secretion for 2 – 3 minutes, which can make the oral cavity secrete enough saliva.
2. Collect Saliva
   • Use the prepared collection container to collect the secreted saliva. If using a collection swab to assist in collection, put the swab into the mouth, rotate it in the oral cavity to allow the saliva to fully adhere to the swab, and then place the swab into the collection container.
   • Try to avoid food debris in the oral cavity from mixing into the saliva sample. If some small food debris accidentally mixes in, you can try to remove it with a clean tool (such as tweezers), but be careful not to lose the saliva sample. The volume of the collected saliva sample generally needs to meet the minimum requirement specified by the collection card, usually around 0.5 – 2 milliliters, depending on the specific requirements of different collection cards.

III. Sample Transfer and Preservation

1. Transfer the Sample to the Collection Card
   • Carefully transfer the collected saliva sample from the collection container to the saliva DNA collection card. This is usually done by smearing the saliva on the collection swab onto the designated area of the collection card, or by slowly dripping the saliva onto the sample window of the collection card.
   • During the transfer process, ensure that the saliva is evenly distributed within the effective area of the collection card to avoid situations where there is too much or too little sample in a local area. Some collection cards may have special coatings or filter – paper structures that can better absorb and fix the saliva sample. Follow the instructions of the collection card for correct operation to ensure that the sample can be effectively absorbed by the collection card.
2. Dry the Sample
   • After completing the sample transfer, the saliva sample on the collection card needs to be dried naturally. Generally, place the collection card in a well – ventilated and dry environment, avoiding direct sunlight. The drying time may vary depending on environmental conditions (such as temperature and humidity), usually ranging from 30 minutes to several hours.
   • Do not touch or move the collection card before the sample is completely dry to avoid damaging the integrity of the sample. After drying, the sample will adhere better to the collection card, facilitating subsequent storage and transportation.

IV. Sample Labeling and Storage

1. Label the Collection Card
   • After the collection card is dry, clearly and accurately label it. The labeling content usually includes the collection date, the name or number of the collection subject, the purpose of the sample, and other important information. Use a waterproof marker pen for labeling to ensure that the labeled content does not blur or disappear during storage and transportation.
2. Store the Collection Card
   • Put the labeled collection card into a special storage bag or envelope to protect the collection card from dust, moisture, and other pollutants. The storage bag or envelope is preferably sealed and can prevent the sample from being squeezed.
   • Store the collection card according to the recommended storage conditions. Generally, it is stored in a dry and dark place at room temperature. If long – term storage is required, some collection cards may need to be stored in a low – temperature environment (such as – 20°C or – 80°C) to ensure the stability of the DNA sample. During the storage process, regularly check the condition of the collection card to ensure that the sample has not been damaged or deteriorated.