Antibody Screen/Antibody ID/Crossmatch Flashcards
IgG antibodies detection
Antibodies with LISS/albumin or PEG potentiator shows reactivity usually in AHG phase
IgM (cold) antibody detection
Antibodies usually show reactivity in the IS phase
IgM broad thermal range
Antibodies show reactivity in IS and 37 degree C
Purpose of patient autocontrol
To see if the patient has an antibody that will attach to their own cells, which also might interfere with the alloantibody search
Purpose of antibody screen
To screen for the presence of unexpected antibodies that are not A, B or A,B
IgG antibodies detected at AHG phase using LISS as a potentiator
Rh system, Kell, Duffy, Kidd, Ss
IgM antibodies detected at IS phase only
M, N, P, Lewis
Antibodies that are most likely cold agglutinins
M, N, P, Lewis, H, I, IH
Advantage of using PEG over LISS/albumin as a potentiator
Enhances strength of reactions
If a patient had a 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 compliment 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 compliment continued to completion
Why is it important to know if you have polyspecific AHG of monospecific AGH?
If compliment is involved or not
What are antibody screen cells?
Type O RBC’s with a wide variety of common antigens
Different probability for meeting 95% predictability
3 pos, 3 neg
2 pos, 5 neg
1 pos, 19 neg
How does dosage appear in the reaction phase of an antibody ID 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 get testing?
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 from washing
Poor washing & unattached antibodies are bound the the free AHG so not available to attach to the check cells
Forgot the AHG reagent
Which antigen/antibody reactions are decreased using enzymes?
Fya, Fyb, MNSs
Which antigen/antibody reactions are increased using enzymes?
D, c, E, e, Jka, Jkb, Lea, Leb, P1, P
Which antigen/antibody reactions don’t show dosage?
D, Lea, Leb, P1 and P
Where are the antigen and antibody from in the autocontrol?
Antigen- patient 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
