What blood collection system uses vacuum in its needles?

The correct answer in this context is the Evacuated System. This system involves the use of vacuum-sealed tubes, which allows for efficient blood collection by utilizing a vacuum to draw the blood into the tube through a needle. When the needle punctures the vein, the pressure difference created by the vacuum in the tube helps to pull the blood quickly into the collection container.

The design of the Evacuated System means that when a sterile needle is inserted into the tube, the vacuum within the tube creates suction, prompting blood to flow directly in. This method minimizes the exposure of blood to the environment, reducing the risk of contamination and ensuring a cleaner sampling process.

Options like the Winged Infusion System and Butterfly Needles are often used for different procedures, primarily in venipuncture for smaller veins or for drawing blood. These systems do not rely on a vacuum mechanism, instead allowing blood to flow through gravity or careful manipulation. The Vacutainer System, while it may sound similar, is essentially a brand name for tubes used with the Evacuated System, but the term "Evacuated System" more specifically describes the mechanism that relies on the vacuum for collection.