Final answer:
In dermal sampling, a capillary stick is often used to collect blood into a small tube with additives like lithium heparin or K2EDTA. The phlebotomists must adhere to specific protocols for each test and record the collection site. After collection, blood may be treated or allowed to clot and centrifuged to separate serum for analysis.
Step-by-step explanation:
When obtaining dermal samples for a blood test, phlebotomists generally use a capillary stick on external skin surfaces such as a finger, an earlobe, or the heel of an infant. This procedure employs capillary action to draw blood into a small diameter glass tube, as seen in medical analysis. The order of draw is critical when collecting multiple tubes to prevent cross-contamination and ensure accurate test results. However, in the context of dermal or capillary sampling, typically only one tube is filled, which commonly contains additives like lithium heparin or K2EDTA to prevent clotting and preserve the blood for analysis.
Phlebotomists must follow standard procedures and protocols set forth in phlebotomy certification programs and are often required to record the site of blood collection for accountability and traceability. In clinical settings, the choice of tube is important to match the specific test for which the blood is collected, such as tubes with K2EDTA for certain hematology tests or lithium heparin when plasma is needed. However, individual institutional protocols may vary, and it is essential for a phlebotomist to be familiar with the specific guidelines of their laboratory.
After blood is collected, it may be immediately processed, as in analytes quenched with methanol, or allowed to clot to obtain serum, as in the case where blood is collected in a glass tube without anticoagulants. The harvesting of serum after about an hour allows the blood to clot, and the non-clotted liquid component is then separated by centrifugation for further analysis.