Specimen collection

Question 1

1. What is the anticoagulant and the percentage of anticoagulant in the routine coagulation collection tube?

Answer 1

3.2% sodium citrate

Question 2

4. What is the ratio of blood to anticoagulant in the citrate tube used for coag testing?

Answer 2

9:1

Question 3

5. Does elevated hct have any effect on specimen collection for coag testing?

Answer 3

No, but if the hct is greater than 55% then an adjustment needs to be made; an elevated hct will cause a falsely elevated clotting time

Question 4

Does anemia affect coag testing?

Answer 4

No

Question 5

What are the effects of overfilling the blue tube?

Answer 5

Reduced clotting time because the the sample has too much blood/clotting factors

Question 6

What are the effects of underfilling the blue tube?

Answer 6

Clotting times are prolonged because the sample is diluted

Question 7

What are the storage requirements for PT?

Answer 7

Room temperature, unstoppered, tested with 24 hours, upright in rack

Question 8

What are the storage requirements for aPTT

Answer 8

Room temperature, tested within 4 hours; IF PT IS ON HEPARIN MUST BE CENTRIFUGED WITHIN 1 HOUR AND SEPARATED AS PPP (platelet poor plasma) AND TESTED WITHIN 4 HOURS

Question 9

why isn’t EDTA used for coag?

Answer 9

It binds calcium more strongly sodium citrate

Question 10

Why isn’t heparin used for coag?

Answer 10

It interferes with factor Xa???

Question 11

What is platelet poor plasma used for?

Answer 11

Platelet aggregation studies (hemostasis)

Question 12

What is platelet rich plasma used for?

Answer 12

Platelet function testing