Immunohematology Exam 2 (ABO Discrepancies, HTLA, Mixed Field,
Transfusions RXNS, AIHA, HDFN ) 2024-2025
HTLA characterictics
- weak reactions when undiluted (low avidity)
- react at high dilutions 1:2048 (high titer)
- weak at AHG phase
- variable strength of reactivity
- nonreactive with autologous cells
- most are high prevalence antigens
HTLA non reactive with ficin treated RBCs
-Anti-Ch, -Rg (Chido Rogers)
•neutralizable: Anti-JMH
Anti-Ch or -Rg
- absorb with autologous RBCs coated with C4d
- use plasma suspended cells
- neutralization
HTLA reactive with ficin treated RBCs
-Anti-Kna, -McCa, -Sla, -Yka. (Knops)
-Anti-Hy, -Gya (Dombrock)
-Anti-Csa (COST collection)
-Anti-Sda
,Detect HTLA antibodies
-RT testing
-fresh panel and donor RBCs
-albumin
-60 min incubation at 37
-AHG phase
-inhibition study: pooled plasma from antigen positive individuals or adsorb with C4
coated cells (anti -Ch, -Rg)
Clinical significance of HTLA antibodies
- most are clinically insignificant
- except anti-Hy and anti-Gya (mild HDN, shortened survival of transfused antigen
positive cells)
- associated with autoimmune disease
ABO Discrepancies Flowchart
Missing/weak forward reactions
A or B Subgroup
Disease States
BGSS
Resolution for Missing/weak in the forward
Wash red cell suspension and incubate for 30 minutes at room temperature with the
addition of anti-A, -B.
, Enzyme treat patient's red cells in order to enhance the reaction.
- Use O red cells as control
Saliva testing
- Only if patient is a secretor
Adsorption/Elution
Describe the use of Adsorptions/Elutions in resolving missing reactions in the forward.
Adsorption/Elution
1) Patient's cells incubated at 4C with appropriate antisera
2) Take the cells with attached antibodies and do an eluate to take those antibodies off
3) Take that eluate and test it against A, B, and O cells
Additional in the forward
Acquired B or B(A) phenotype
Polyagglutination
Rouleaux
Cold autoantibodies
Contamination in reagent/Reagent dye
Bone Marrow Transplant
How does the (B)A phenotype give an extra reaction in the forward? How is it resolved?
High levels of B galactosyltransferase transfers small amounts of the A sugar to the H
antigen
- Detected by murine monoclonal antibody in reagent (MHO4)
Transfusions RXNS, AIHA, HDFN ) 2024-2025
HTLA characterictics
- weak reactions when undiluted (low avidity)
- react at high dilutions 1:2048 (high titer)
- weak at AHG phase
- variable strength of reactivity
- nonreactive with autologous cells
- most are high prevalence antigens
HTLA non reactive with ficin treated RBCs
-Anti-Ch, -Rg (Chido Rogers)
•neutralizable: Anti-JMH
Anti-Ch or -Rg
- absorb with autologous RBCs coated with C4d
- use plasma suspended cells
- neutralization
HTLA reactive with ficin treated RBCs
-Anti-Kna, -McCa, -Sla, -Yka. (Knops)
-Anti-Hy, -Gya (Dombrock)
-Anti-Csa (COST collection)
-Anti-Sda
,Detect HTLA antibodies
-RT testing
-fresh panel and donor RBCs
-albumin
-60 min incubation at 37
-AHG phase
-inhibition study: pooled plasma from antigen positive individuals or adsorb with C4
coated cells (anti -Ch, -Rg)
Clinical significance of HTLA antibodies
- most are clinically insignificant
- except anti-Hy and anti-Gya (mild HDN, shortened survival of transfused antigen
positive cells)
- associated with autoimmune disease
ABO Discrepancies Flowchart
Missing/weak forward reactions
A or B Subgroup
Disease States
BGSS
Resolution for Missing/weak in the forward
Wash red cell suspension and incubate for 30 minutes at room temperature with the
addition of anti-A, -B.
, Enzyme treat patient's red cells in order to enhance the reaction.
- Use O red cells as control
Saliva testing
- Only if patient is a secretor
Adsorption/Elution
Describe the use of Adsorptions/Elutions in resolving missing reactions in the forward.
Adsorption/Elution
1) Patient's cells incubated at 4C with appropriate antisera
2) Take the cells with attached antibodies and do an eluate to take those antibodies off
3) Take that eluate and test it against A, B, and O cells
Additional in the forward
Acquired B or B(A) phenotype
Polyagglutination
Rouleaux
Cold autoantibodies
Contamination in reagent/Reagent dye
Bone Marrow Transplant
How does the (B)A phenotype give an extra reaction in the forward? How is it resolved?
High levels of B galactosyltransferase transfers small amounts of the A sugar to the H
antigen
- Detected by murine monoclonal antibody in reagent (MHO4)
