Week 1 Lab

Question 1

what are the usual concetrations used for the tube method of red cell preparation?

Answer 1

2-5%

Question 2

what is the usual concentration used for the gel method of red cell preparation?

Answer 2

around 8%

Question 3

Zonal reactions cause ?

a. false positive
b. false negative
c. true positive
d. true negative

Answer 3

b. false negative
as zone of equivalence is not reached

Question 4

what is the zone of equivalence?

Answer 4

optimum number of antigens and antibodies

Question 5

what is the cause of the prozone effect?

Answer 5

excess of unbound immunoglobulin

Question 6

what leads to the post zone effect?

Answer 6

excess of antigen

Question 7

what type of blood is used in the red cell suspension

a. coagulated
b. anticoagulated
c. both
d. neither

Answer 7

b

Question 8

What is the diluent used in red cell preparation

Answer 8

NSS 0.9%

Question 9

to separate the plasma and the red cells what should the centrifuge speed be? (and for how long)

Answer 9

3000 rpm for 2 minutes

Question 10

T or F

the tube where the red cells are transfered should be labelled with the patient’s full name

Answer 10

F (initials only)

Question 11

after transferring the 0.5 ml of packed red cell, how much NSS should be added to the tube?

Answer 11

3/4 of the tube

Question 12

what are the centrifuge settings when washing the packed red cell?

Answer 12

3000 rpm for 20 seconds
(ideally 20 seconds but may be adusted if there are still red cells on the side of the tube)

Question 13

how many times are the packed red cells washed?

Answer 13

3-4 times

Question 14

what is the formula in preparing the 5% red cell suspension?

Answer 14

total volume = (volume of WRBC / %) x 100

Question 15

what is the color of a proper 5% red cell suspension?

Answer 15

tomato red / cherry red