3S [LAB]: Sources of Error

Question 1

Determine the effect of error on APTT/PT:

Short draw

Answer 1

Falsely prolonged

Question 2

Determine the effect of error on APTT/PT:

Hct >55% (PV patients)

Answer 2

Falsely prolonged

Question 3

Determine the effect of error on APTT/PT:

Large clot in tube

Answer 3

Falsely prolonged

Question 4

Determine the effect of error on APTT/PT:

Heparin contamination from line draw

Answer 4

Falsely prolonged

Question 5

Determine the effect of error on APTT/PT:

Lipemic sample

Answer 5

Falsely prolonged (in optical method)

Question 6

Determine the effect of error on APTT/PT:

Icteric sample

Answer 6

Falsely prolonged (in optical method)

Question 7

Determine the effect of error on APTT/PT:

Hemolysis

Answer 7

Falsely shortened

Question 8

Determine the effect of error on APTT/PT:

Small clot in tube

Answer 8

Falsely shortened

Question 9

Determine the effect of error on APTT/PT:

Plasma containing platelet (not platelet poor)

Answer 9

Falsely shortened

Question 10

Determine the effect of error on APTT/PT:

Fishing in blood collection

Answer 10

Falsely prolonged

Question 11

APTT should be done within ___

Answer 11

4 hours

Question 12

PT should be done within ___

Answer 12

24 hours

Question 13

Usual concentration (in percent) of citrate in light blue tube

Answer 13

3.2%

Question 14

Usual amount (in mL) of citrate in light blue tube

Answer 14

0.5mL

Question 15

Usual concentration (in percent) of blood in light blue tube

Answer 15

4.5mL

Question 16

Proper blood to anticoagulant ratio in light blue top

Answer 16

9:1

Question 17

Proper blood to anticoagulant dilution in light blue top

Answer 17

10:1

Question 18

Remedy for PV patient

Answer 18

Reduce the volume of anticoagulant