Why are there different colored tubes for drawing blood?

What do the colors of the vessels represent?

We got the answer in the clinical lab.

Students saw the strict division of the laboratory, including blood tests, biochemical tests, microbial tests, etc., and learned about the operation of inspection equipment. In particular, the students participated in how a tube of blood passed through the automated equipment, plus the professional analysis of the inspectors, and finally, got a complete inspection report.