What feature do vacuum collection tubes possess?

Vacuum collection tubes are designed with a vacuum seal that allows for automatic filling when the tube is attached to a needle for blood collection. This vacuum creates a negative pressure inside the tube, which draws the blood into the tube once the needle punctures the vein. The specific volume of blood collected is determined by the size of the tube and the vacuum pressure, ensuring consistent fill levels for accurate sample volumes.

The other features mentioned in the choices do not apply to vacuum collection tubes in the same way. While some tubes can be coated with anticoagulants, not all tubes have this feature, as some are meant for serum collection with no additives. Reusability is not a characteristic of vacuum tubes; they are intended for single use to maintain sterility and prevent contamination. Lastly, the built-in needle concept does not apply since vacuum collection tubes require a separate needle, typically held in a holder, to facilitate blood collection.