Total WBC plus relative (%) and absolute counts of all white blood cell types
Tube fill capacity
Lavender-top (EDTA) tube
Invert tube 8 to 10 times immediately after tube is filled at the time of collection.
Maintain specimen at room temperature for 24 hours; refrigerate for 48 hours.
Causes for Rejection:
Hemolysis; clotted specimen; tube not filled with minimum fill volume; specimen diluted or contaminated with IV fluid; specimen drawn in any anticoagulant other than EDTA; transfer tubes with whole specimen received with plasma removed (plasma used for other testing); improper labeling; samples more than 72 hours old.
Determine quantitative variations in white cell numbers and types