reagents may be placed in any sequence along the length of the tube in this way all of the different reagents needed for a multi step diagnostic test may be provided in a given length of tubing alternatively reagents for different diagnostic tests may be placed in separate chambers of the tubing in some tests it may be useful to place a filter in one or more of the segments in order to separate a desired component from a sample for further analysis for example some tests are typically performed using blood plasma as a sample requiring separation of the plasma from whole blood such a separation may be accomplished with the present invention by delivering whole blood into one side of a tube segment which contains an appropriate blood filter and using vacuum pressure to draw plasma through the filter to the other side of the tube segment filtered plasma can then be extracted from the tube and delivered to another segment by a receipt dispense needle for further testing the tubing containing reagents may be incorporated into a system with the appropriate devices for delivering a sample to or drawing a sample from the inside of the tube such devices may comprise any useful arrangement of receipt dispense needles with syringes capillary tubes or other devices capable of piercing the tubing and conveying a sample in combination with any.