Week 13 - Case Studies in Transfusion

Question 1

What do Schistocytes Indicate?

Answer 1

Intravascular Haemolysis

Question 2

What does Elevated LDH and Bilirubin with Decreased Haptoglobin Indicate?

Answer 2

Haemolysis

Question 3

What do Spherocytes Indicate?

Answer 3

Haemolytic Anaemia

Question 4

How to Prove if an IgM Antibody is Present in Plasma

Answer 4

Treat plasma with dithiothreitol (DTT)

Question 5

What usually Accompanies an IgM Antibody?

Answer 5

Positive C3 (complement)

Question 6

What does a Negative Donath-Landsteiner Test Indicate?

Answer 6

Rules out paroxysmal cold haemoglobinuria (PCH)

Question 7

Differential Diagnosis for a Positive DAT with an IgG and have been Treated with IVIg

Answer 7

Warm AIHA
Drug-induced haemolytic anaemia
Passive antibody from IVIg
Hypergammaglobulinaemia from IVIg

Question 8

Reasons why anti-D might be present

Answer 8

Previous RBC transfusion
Pregnancy
Passive anti-D in IVIg

Question 9

What can IVIg Contain?

Answer 9

Anti-A and anti-B

Question 10

What does varying reaction grades show on an antibody screen?

Answer 10

Multiple antibodies

Question 11

In this image, why is there no reaction in cells that show positivity for Jka?

Answer 11

Kidd and Duffy antibodies demonstrate dosage
If the antibody is weak (1+ reactions in this instance), it will only react against cells that have homozygous expression of the corresponding antigen

Question 12

Using the frequency table, how many units would have to be screened to find a single unit of antigen negative blood? Patient has an anti-e and anti-Jka and potential anti-K and anti-S
Assume all units are group specific (B pos)

Answer 12

Because all units are group specific, can exclude those percentages
(e-) 0.024 x (K-) 0.909 x (Jka-) 0.236 x (S-) 0.48 = 0.0024
0.0024 = 0.247%
To find the amount of units needed to be screened to find antigen negative blood: 1/0.00247 = 404.8
Therefore 405 units need to be screened

Question 13

Using the frequency table, in a population of 1000, how many could provide group-specific compatible blood to this individual? Patient is O pos and has an anti-K and anti-E

Answer 13

(O) 0.461 x (D+E-) 0.544 x (K-) 0.909 = 0.228
D+E-: 35.3+17.5+1.6 = 54.4%
0.228 = 22.8%
1000 x 0.228 = 228
Therefore 228 people could provide group specific compatible blood

Question 14

When performing an alloadsorption on somone how has WAIHA, what cells should you use if their phentype is AB Rh(D) pos, C+ E- c- e+; K- k+; Jk(a-b+); Fy(a+b-)

Answer 14

c-, E-, K-, Jk(a-), Fy(b-)
This is done as the patient can produce antibodies to these antigens

Question 15

If performing an alloadsorption and the patient has this phenotype: C+ E- c- e+; K- k+; Jk(a-b+); Fy(a+b-), and we want to enzyme treat the cells, which antigen(s) become negative?

Answer 15

Duffy antigens (Fya)
We use enzyme treated cells as it increases antibody uptake

Question 16

Patient with phenotype Ab pos, C+ E- c- e+; K- k+; Jk(a-b+) has a positive antibody screen, which cells can we expect the antibody to NOT be even if it shows positivity on the screen?

Answer 16

anti-D, anti-C, anti-e, anti-k, anti-Jkb
Because the patient is positive for these antigens

Question 17

Difference between Apheresis and Random Donor Platelets

Answer 17

Apheresis platelets, blood is taken from patient and spun with patient still there, red cells put back into patient
Therefore only platelets in plasma are taken
Apheresis platelets come from a single donor, random platelets come from multiple donors

Question 18

Patient has been transfused platelets, they have a positive auto control, so DAT is done. DAT is positive, but eluate is negative, why?

Answer 18

ABO antibodies

Question 19

Patient has ABO discrepancy in reverse group in the A1 cells, antibody screen is negative. Does this help narrow down what is causing this discrepancy?

Answer 19

Yes
Shows it is not a cold reacting antibody, most likely to be an ABO antibody

Question 20

Patient has ABO discrepancy in reverse group in the A1 cells, antibody screen is negative. Does this help narrow down what is causing this discrepancy?

Answer 20

Yes
Shows it is not a cold reacting antibody, most likely to be an ABO antibody

Question 21

All panel cells positive, with uniform reaction strength and a negative auto-control

Answer 21

Antibody against high frequency antigen

Question 22

Most (or all) panel cells positive with 1+ reactions, negative auto-control

Answer 22

High titre, low avidity ‘like’ antibodies

Question 23

What does this show?

Answer 23

Ch/Rg antibody
Test sample has been neutralised and the reactivity has become negative = CH/Rg antibody

Question 24

What can positive auto control help to differentiate between?

Answer 24

Autoantibody and an antibody against a high frequency antigen

Question 25

What does panagglutination with a positive auto control show?

Answer 25

Warm AIHA

Question 26

What does panagglutination, positive DAT, positive auto control but a negative eluate suggest?

Answer 26

Drug induced immune haemolytic anaemia

Question 27

Difference between PCH and CAD

Answer 27

PCH causes intravascular haemolysis and CAD causes extravascular haemolysis
This is why PCH patients shows hemoglobinemia and hemoglobinuria