1, 2. Antibody Investigation

Question 1

Anti-I (big I) is __ with adult cells and __ with cord cells

Answer 1

POS with adult cells

NEG with cord cells

Question 2

_____ antibodies are special kinds of high frequency antigens

Answer 2

HTLA (high titre, low avidity)

Question 3

This antibody is RARE and sometimes associated w/ infectious mononucleosis

Answer 3

anti-i (small i)

Question 4

This antibody determination procedure is NOT recommended if the patient recently received a transfusion

Answer 4

autoadsorption

Question 5

Can cause cold hemagglutinin disease

Answer 5

auto-anti-I (big I)

Question 6

What is ZZAP

Answer 6

papain/ficin + DTT

Question 7

Purpose of ZZAP?

Answer 7

Used to get rid of autoantibodies

Sulfhydrl reagent removes IgM abs from cells, then the enzymes enhance uptake of autoantibody

Question 8

Term meaning “weak reactions, even when undiluted (neat) plasma is used”

Answer 8

Low avidity

Question 9

How to neutralize HLA antibodies?

Answer 9

Use human platelet concentrate (HPC) => platelets contains lots of HLA antigens => adsorption

Question 10

This reagent enhances IgM antibodies and should be avoided when there’s a cold antibody

Answer 10

LISS

Question 11

The purpose of additional procedures when working up a warm autoantibody?

Answer 11

Identify potential underlying alloantibodies

Question 12

Antibodies in this system are sensitive to sulfhydryl reagents

Answer 12

Kell

Question 13

Autoantibodies cause DAT to be almost always positive due to ____ and maybe ___

Answer 13

always - C3

maybe - IgG

Question 14

Last resort when other options don’t eliminate the cold autoantibody?

Answer 14

Adsorption at 4 degC

Question 15

The presence of this disease will usually cause crossmatches to be all incompatible => give the least incompatible blood

Answer 15

WAIHA (warm autoimmune hemolytic anemia)

Question 16

Traditionally called Bg antigens

Answer 16

Human leukocyte antigens (HLA)

Question 17

How do you know if you have one of the “routine exclusion is not usually required” antibodies?

Answer 17

Screen is negative but crossmatch is positive

Question 18

To avoid cold antibodies reactivity, why is anti-IgG used instead of polyspecific AHG reagent?

Answer 18

Anti-IgG doesn’t detect attachment of complement (most cold antibodies are C3 positive)

Question 19

Alternative to using patient’s own cells for adsorption is the use of ________

Answer 19

RESt (rabbit erythrocyte stroma kit)

Question 20

The procedure that removes intact antibodies from the red cell membranes is?

Answer 20

elution

Question 21

Selected cells must be _________ for the antibody identified and __________ for the CRO

Answer 21

negative; positive

Question 22

How to eliminate cold antibody reactivity?

Answer 22

Pre-warm technique

Question 23

Term meaning “not easily diluted out, persistent”

Answer 23

High-titre

Question 24

What is a cold panel and its purpose

Answer 24

Test patient plasma w/ adult AND cord cells

To detect anti-I (big I)

Question 25

High freq antigens occur at a frequency of ___%

Answer 25

98%

Question 26

Unless it’s this disease, cold autoantibodies are usually not clinically significant

Answer 26

cold agglutinin

Question 27

2 objectives in antibody investigation?

Answer 27

1. Identify the antibody(ies) that are present
   - single Ab specificity
   - multiple Ab resolution
2. Make sure no other antibodies are present

Question 28

These 3 reagents enhance warm antibodies

Answer 28

LISS, PEG, enzymes

Question 29

4 high frequency antibodies (>98%)

Answer 29

• k
• Kp^b
• Js^b
• Lu^b

Question 30

How to tell if an antibody being ID’d is in the Kell system?

Answer 30

Initially positive for all cells tested, treat w/ sulfhydryl reagent, re-test => should all become negative

Question 31

Patient history w/ pneumonia suggests which disease?

Answer 31

Cold autoimmune disease

Question 32

Are HTLA antibodies usually clinically significant?

Answer 32

No, but they need to be removed to identify underlying alloantibodies

Question 33

A very strong _________ can cause cold agglutinin disease

Answer 33

auto-anti-I

Question 34

How to identify cold antibodies?

Answer 34

Incubate panel at RT or lower to enhance rxns

Question 35

Possible reason for an entire panel being negative?

Answer 35

Low frequency antigen

Question 36

3 key points of a typical reaction pattern when HTLA antibody present

Answer 36

• Weak rxns at the IAT phase
• Variable rxns among panel cells
• Inconsistent rxns that are sometimes NOT reproducible

Question 37

Problem with HTLA antibodies even though they don’t cause HDFN or transfusion rxns?

Answer 37

May mask clinically significant antibodies

Question 38

The procedure that removes intact antibodies from the red cell membranes is?

Answer 38

autoadsorption

Question 39

Patient history w/ lupus or carcinoma suggests which autoantibody?

Answer 39

Warm autoantibody

Question 40

Significance of HLA antibodies?

Answer 40

Can mask other antibodies or interfere with testing

Question 41

What type of antibody would be responsible for causing antigram to have almost all positive, same phase, same strength?

Answer 41

High-frequency antibody

Question 42

These reagents denature IgM

Answer 42

sulfhydryl

Question 43

Type of antibodies that can be adsorbed using RESt?

Answer 43

Cold autoantibodies