Chapter 3 Flashcards
Most IgG antibodies are detected in what reaction phase?
-IgG - antibodies with LISS/albumin or PEG potentiator shows reactivity usually in AHG phase
What is the purpose of a patient autocontrol?
To see if the patients have an antibody that will attach to their own cells, which also might interfere with the alloantibody search
Describe the blood type, Rh type, and other antigens on surface of antibody screen cells:
Type:
Rh:
Type: Type O RBCs
Rh: Both Pos and Neg
Other antigens: Different cell lines express different antigen combinations of D, C, c, E, e, V, Cw, K, k, Kpa, Kpb, Jsa, Jsb, Fya, Fyb, Lea, Leb, P₁, M, N, S, s, Lua, Lub, Xga
Cold IgM antibodies are detected in what phase?
antibodies usually show reactivity in the IS phase
Broad thermal range IgM antibodies are detected in what phase?
-IgM-broad thermal range - IS and 37°C
Describe the procedure of an unexpected antibody screen.
- 2 drops pt. serum in screen cell tubes 1,2,3
- 1 drop screen cells in respective tubes
- add 2 drops LISS
- incubate 10 min at 37°C
- centrifuge - record reaction
- wash 3x
- add 2 drops AHG
- centrifuge/read and record macro/micro
- if neg. rxn. in 8, add Check cells
- centrifuge/read and record
What is the purpose of an antibody screen?
-to screen for the presence of unexpected antibodies (not A, B, AB antibodies)
Discuss the IgG antibodies detected at AHG phase using LISS as the potentiator:
Rh system, Kell, Duffy, Kidd, Ss
Discuss the IgM antibodies detected at IS phase only:
M, N, P, Lewis
List the antibodies that are most likely cold agglutinins?
M, N, P, Lewis, H, I, IH
What is the advantage of using PEG over LISS or albumin as a potentiator?
Enhances strength of reactions
If a patient had broad thermal range IgM antibody where would the reactions take place in the antibody screen if LISS was used as the potentiator and you used anti-IgG AHG?
IS and 37
If complement has been activated, what evidence of this would you see in your test tube:
Agglutination with polyspecific AHG
-May show hemolysis if serum is used and complement continued to completion
Why is it important to know if you have polyspecific AHG or monospecific AHG?
If complement is involved or not
You need to do antigen typing on both the patient and donor units.
A. Why are you antigen typing the patient?
B. Where else do you need to do antigen typing
A: Assist in the confirmation that the patient does not have the antigen that corresponds to the unexpected antibody
B:The two donor units
What are antibody screen cells?
Type O RBCs with a wide variety of common antigens
If you suspected a second antibody may also be hidden on an antibody identification panel, how would you have suspected this and how would you pursue the hunt
The strength of the reactions
Discuss the different probability for meeting 95 predictability other than the 3 pos and 3 neg cell lines for antibody confirmation
2 pos and 5 neg
1 pos and 19 neg
Discuss how dosage would appear in the reaction phase of an antibody identification panel.
Whenever the corresponding antigen (to patients unexpected antibody) is expressed homozygously, a stronger strength of agglutination is frequently apparent in contrast to the cell lines when the antigen is only expressed heterozygously.
How can you determine if the patient has an unexpected broad thermal range IgM antibody when you are doing gel testing in transfusion services?
May miss it because AHG would be anti-IgG, you might catch it if the crossmatch tube is not compatible at IS phase
If the check cells don’t show agglutination in an unexpected antibody screen, what might have gone wrong?
Too much saline left, poor washing and unattached antibodies are bound to the free AHG so not available to attach to the check cells or forgot the AHG reagent
In tube testing how can you distinguish between warm and cold reacting antibodies?
Avoid using IS phase.
In what phases would a broad thermal range IgM likely appear using LISS as the potentiator and anti-IgG only as the AHG reagent?
IS 3+
37 3+
AHG =
In what phases would a broad thermal range IgM likely appear using PEG as the potentiator and polyspecific AHG?
IS 3+
37 =
AHG 3+
In what phases would a broad thermal range IgM likely appear using LISS as the potentiator and polyspecific AHG reagent?
IS 3+
37 3+
AHG 3+
4 Best choices for donor types for the following blood types?
A pos
A pos
A neg
O pos
O neg
4 Best choices for donor types for the following blood types?
A neg
A neg
O neg
O neg
O neg
4 Best choices for donor types for the following blood types?
B pos
B pos
B neg
O pos
O neg
4 Best choices for donor types for the following blood types?
B neg
B neg
O neg
O neg
O neg
4 Best choices for donor types for the following blood types?
O pos
O pos
O neg
O neg
O neg
4 Best choices for donor types for the following blood types?
O neg
O neg
O neg
O neg
O neg
4 Best choices for donor types for the following blood types?
AB pos
AB pos
AB neg
A pos
A neg
4 Best choices for donor types for the following blood types?
AB neg
AB neg
A neg
O neg
O neg
Which antigen/antibody reactions are decreased using enzymes?
Fya, Fyb, MNSs
Which antibody/antigen reactions don’t show dosage?
D, Lea, Leb, P1 and P
Where are the antigen and antibody from in the autocontrol?
Antigen - patients RBCs
Antibody - patient serum/plasma
Why do you do an autocontrol?
To make sure that an unexpected antibody is not an autoantibody
Where is the antigen from and the antibody from in a crossmatch tube?
Antigen - donor RBCs
Antibody - Patient serum/plasma
If you need 2 units of packed cells for your patient that has an unexpected antibody—what formula do you use?
2 divided by the % of donor population without the antigen
You need 4 units of packed rbc’s for a patient that is an O pos and has anti-C.
The antigen frequency in your donor population for C is 70%.
a. What is your first and second choices for the type of rbcs’ you are selecting.
b. How many units are you estimating must be antigen typed to find 4 untis that are C antigen negative?
O pos, O neg
4 divided by 0.30 = about 14 units
Which antigen/antibody reactions are increased using enzymes?
D, C, c, E, e, Jka, Jkb, Lea, Leb, P1, P
4 Forms of polyagglutination
T, Tk, Tx, Th
Identify the Rh antigen frequencies in terms of % of compatible blood for a patient with Rh antibodies.
D - 93.7 C - 87 c - 58 E - 20 e - 98
In what population are you most likely to find Jk(a-b-)
Polynesians
Frequency for Fy(a) and Fy(b) in whites
Fy(a) = 66 Fy(b) = 83
Frequency for Fy(a) and Fy(b) in blacks
Fy(a) = 10 Fy(b) = 23
Frequency of Fy(a-b+), Fy(a+b+), Fy(a-b-), Fy(a+b-)
Fy(a-b+) - whites 34
Fy(a+b+) - whites 49
Fy(a-b-) - blacks 68
Fy(a+b-) - Chinese 91
Frequency of Jk(a+b-), Jk(a+b+)
Jk(a+b-) - blacks 51
Jk(a+b+) - Whites and Chinese 50
