Answer to Question 1
ANS: B
EDTA is the anticoagulant agent of choice for routine hematology testing; it is found in the purple top tube. For routine coagulation testing, 3.2 sodium citrate in the blue top is used, whereas heparin in the green top tube is used for some special tests, primarily in clinical chemistry.
Answer to Question 2
ANS: C
Fasting is not required to obtain a valid specimen for a CBC. Heparin is not the appropriate anticoagulant agent for a CBC. Coagulation tests should not be performed on a hemolyzed sample. The fluid in the intravenous line will contaminate a CBC drawn above an intravenous line, and all blood cell counts will be diluted and thus invalidly decreased.