Which statement about blood collection tubes is correct?

The statement regarding vacuum drawing blood into evacuated tubes is accurate because the design of these tubes includes a vacuum-sealed environment that allows for easy collection of blood. When the puncture needle is inserted into the patient's vein, the difference in pressure between the external environment and the evacuated tube causes blood to flow into the tube automatically, facilitating a sterile and efficient collection process. This is essential in clinical settings, especially when multiple samples are needed, as it helps speed up the process and reduces the likelihood of contamination.

The other statements, while related to blood collection, do not correctly convey how blood collection tubes function or their characteristics. For instance, the filling order of tubes is regulated by the additives they contain, and color coding does exist for tubes with stoppers, serving as tools for health professionals to quickly distinguish between them and their respective uses. Understanding these elements is vital for operating within a clinical structure and ensuring accurate and effective blood collection.