What are the consequence for blood specimen collection when a vacuum tube takes a very long time to fill?

If a vacuum tube takes a very long time to fill during blood specimen collection, it can lead to hemoconcentration where the blood cells become concentrated due to prolonged contact with the tube walls. This can affect the accuracy of test results as the proportion of blood cells to plasma may be altered. Additionally, prolonged exposure to air can cause changes in blood composition and potentially lead to inaccurate test results.