Bloodbank Exam 2

Serology 6-11 NEED TO ADD ABO DISCREPENCIES AND SPECIAL TECHNIQUES

Frequency of D antigen

85%

Frequency of C and c antigen

Big: 70%

Little: 80%

Frequency of E and e antigen

Big: 30%

Little: 98%

R0 Haplotype

Dce

R1 Haplotype

DCe

R2 haplotype

DcE

Rz Haplotype

DCE

r haplotype

dce

r’ haplotype

dCe

r” haplotype

dcE

ry Haplotype

dCE

Haplotypes: 1 or ‘ has a capital …

Capital C

Haplotypes: 2 or “ has a captial …

E

Haplotypes with a letter have

Both Capital C and E

Characteristics of Anti-D

Immune Stimulated

IgG (1 or 3)

Can be prevented with RhIG

Clinically Significant for both Transfusion Reaction and HDFN

Other Rh System (C,c,E,e) Characteristics

Immune Stimulated

IgG

Clinically Significant for Transfusion and HDFN

Can Show Dosage Effect

Frequency of Kell (Anti-K)

9%

Frequency of k

98.8%

Frequency of Kpa and Jsa

Low Frequency Antigen (rare)

Frequency of Kpb and Jsb

99-100%

Characteristics of Kell

Antigens well developed at birth*

Very Immunogenic

Immune Stimulated Antibody

Primarily IgG

Clinically Significant in Transfusion and HDFN

Destroys precursor red cells in the bone marrow

Frequency of Fya

W: 65% B: 10%

Frequency of Fyb

W: 80% B: 23%

Frequency of Fy a- b-

W: rare B: 68%

Characteristics of Duffy

a- b- resistant to p. vivax

Antigens well developed at birth

Immune Stimulated

IgG

Clinically Significant in Transfusions and HDFN

Frequency of Jka

77%

Frequency of Jkb

73%

Characteristics of Kidd System

Immune Stimulated

IgG

Antigen acts as urea transporters

Clinically Significant in HDFN (Mild) and Transfusion reactions (mostly extravascular hemolysis)

Frequency of M

78%

Frequency of N

72%

Frequency of S

55%

Frequency of s

89%

Characteristics of M and N

Naturally occuring

BOTH IgM and IgG (Mostly G)

Clinically Significant if it’s an IgG

Exhibits dosage

Characteristics of S and s

Immune stimulated

IgG (rare IgM)

Clinically significant in Transfusion and HDFN

Frequency of Lea

22%

Frequency of Leb

72%

How is the Lewis gene inherited

If you DON’T inherit the Lewis gene, you are a- b-

If you DO inherit the Lewis gene, you are a+ b-

If you inherit BOTH the Lewis gene and the Secretor gene, you are a+ b+

Characteristics of Lewis System

Naturally Occurring

IgM

NOT CLINICALLY SIGNIFICAN

Antigen Produced by Tissue cells

Can be lost during Pregnancy (Brendemoen’s Phenomenon)

Frequency of P1

79%

Characteristics of P1

Naturally Occurring

IgM

Not clinically significant

can be neutralized by P1 substances (hydatid cysts)

Frequency of Lua and Lub

8% and 99.8%

Characteristics of Lua

Naturally occurring

IgM

NOT CLINICALLY SIGNIFICANT

Can give appearance of mixed field/string agglutination

Characteristics of Lub

Immune Stimulated

IgG

Mild HDFN due to poor antigen expression on cord cells

Mild to Moderate Transfusion Reaction

Characteristics of Xga

X-linked chromosome

IgG

Sometimes Naturally Occurring

NOT CLINICALLY SIGNIFICANT

High Titer Low Avidity Antibodies

Antibodies to high incidence antigens which give a weak reactivity at a titer >64

Characteristics of High Titer Low Avidity Antibodies

IgG

NOT CLINICALLY SIGNIFICANT

Chido, Rodgers, Cost-sterling, York, Knops, McCoy, JMH

Antibodies against High Prevalence Antigens

Antigens found in over 99% of the population

All Panel Cells will react except Auto Control

Antibodies to Low Prevalence Antigens (ATLIA)

Antigens present in only 1% of the population

Clinically significant if unable to determine specificity

Characteristics of Cold Autoantibodies

All panel cells including Auto react at IS

IgM

DAT positive for Complement

Includes: I, i, HI, H, P

May interfere with ABO typing

Characteristics of Warm Autoantibodies

All Panel Cells and Auto are positive at AHG

IgG

DAT positive at IgG

Confirm by preforming Elution

Clinically SIGNIFICANT Antibodies

ABO, Rh, Kell, Kidd, Duffy, Ss, Lub, (MAYBE: M, N depending on reaction temp)

NOT clinically significant antibodies

Lewis, P1, Lua, Xga, HTLA

When is Weak D tested

Donors

Newborns

Patients with w+ or 1+ reactions at IS

3 Mechanisms for Weak D

Transmissible Genes

Weak D (Position Effect)

Partial D

Weak D Transmissible Genes

Genetics code for Reduced Expression of D Antigen

Weak D Positive Effect

Weakening of the D antigen due to C gene in Trans (-c-, -C-)

Weak D Partial D

Lack or have altered D epitopes with the entire D protein (antigen build different than normal D)

Which Weak D can produce Anti-D

Partial D

The G antigen is present on cells containing

C or D antigen

The f antigen is present on cells containing

c and e inherited in the cis position (Dce or dce)

Definition of Elution

Removal of Antibody from Red Cells to identify the antibody that is coating them

Reasons for Preforming Elution

Confirm warm auto antibody

Evaluate Transfusion Reaction

Lui Freeze Thaw Elution Method

Red Cells Lyse during freezing, levels the previously bound antibody left

Quick, Small Volume Needed, Used for ABO, Poor Recovery of other Antibodies

Heat Elution Method

Used for ABO, Easy, Poor Recovery of IgG Allo and Auto

Acid Elution Method

Used for Warm auto and allo, easy with commercially available kits, possible false positive with high titer antibodies

Glycine HCl/EDTA, Citric Acid

Chemical/Organic Solvent Elution Method

Reduces surface tension which unbinds the coating antibody

Used for Warm auto and allo, dangerous chemical hazards

Xylene, Digitonin, Dichloromethane DCM

Define Adsorption

Adding antibodies to RBCs in order to identify the antibodies that are left over in the serum/plasma

Applications of Adsorption

Removing an autoantibody to identify underlying allos

Separating multiple antibodies to aid in ID

Confirming Antibody Specificity

Confirming Weak Antigen

Enzymes Destroy

Duffy, MNSs, Xga

Enzymes Enhance

RH, Kidd, Lewis, P1

DTT and EGA destroy

Kell blood group antigens

ZZAP contains

Both enzymes and DTT

Autologous Adsorption Method

Using RBCs from the patient to remove Auto antibodies and Leaves Allo antibodies behind for ID

NO Recent Transfusions

Adequate sample volume needed

Homologous Allo-adsorption Method

Phenotypically similar donor, only 1 pt aliquot needed, possibility of missing antibodies to high incidence antigens

Used when Recently Transfused, Inadequate cell volume

Differential Allo-adsorption method

3 different patient aliquots needed

Must have an R1R1, R2R2, and rr donor

Must have Jka-b+ and Jka+b-

One must be K-

Acceptable ABO Reactions

2+ or greater rxns, NO mixed fields

What are Cryptantigens

Normally hidden but can be exposed post viral infection revealing T, Tk, Tn, Cad

Polyagglutination Acquired B

Infection causing the A antigen to be edited to look chemically similar to the B antigen, which mimics a positive B antigen reaction

Examples of Extra Antibody in ABO Discrepancies

Anti-A1 due to subgroup

Cold Allo or Auto

Rouleaux

Passive Antibody from Transfusion or IVIG

Example of Weak/Missing Antibody in ABO Discrepancy

Newborn, Elderly, Immunocompromised

Diluted plasma (from line draw)

ABO Incompatible Stem Cell Transplant

Subgroup

Examples of Weak/Missing Antigen

A or B subgroup

Hematologic malignancies

GI malignancies

Saline Replacement

Used for Rouleaux

Tube spun, serum removed, equal volume saline added, spun and read to assess red cell agglutination

Pre-Warm Serum to Inactivate IgM

Performed after antibody specificity has been identified

Used to determine if that antibody is Clinically Significant for Transfusion

All Reagents and Patient Sample kept at 37C

DTT Treatment of Serum

Used to determine if a classic IgM antibody that is reacting at IS and AHG phase is clinically significant to HDFN

DTT destroys IgM which helps to detect if there is an IgG is present

If Positive after treatment at DTT, you must titer the antibody

Serum Acidification

Enhances activity of weak reactive IgM

0.1 N HCl added to serum to lower ph

may also decrease reactivity of another antibodies

Increased Serum-to-Cell Ratio

enhances reactivity of antibodies present in low concentration

BUT may cause prozone effect

Antigens Destroyed by Enzymes

M, N, S, s, Fya, Fyb, Xga

Antigens Destroyed by DTT, EGA, AET, 2-ME

Kell System (K, k, Kpa, Kpb)

Why do we use Enzymes or DTT to destroy antigens?

Antibody confirmation, Cross-offs when multiple antibodies present, MM patients on DARA

Antibodies enhanced by Enzymes

Kidd, Rh, Lewis, Anti-P1

Donath-Landsteiner Test

3 Sets of Tubes: 3 incubated at Cold, 3 incubated at Warm, 3 tested Biphasic

Tube 1 is Patient

Tube 2 is mix of Patient and Donor Control

Tube 3 is Donor Control

Rh Prevalence in Order for Whites

R1, r, R2, R0

Rh Prevalence for Blacks

R0, r, R1, R2

The Last Wash Before performing the Elution process should be … because…

Negative because you have washed out all the unbound antibody so you can remove the bound antibody to specifically test that antibody

Treatment Reagents for Adsorption

ZZAP and Enzymes (Papain, Ficin, etc)

Treatment Reagents for Elutions

DTT or EDTA Glycine (EGA)

What Alloantibodies can be ruled out using UNTREATED adsorbate

D, C, E, c, e, K, Fya, Fyab, Jka, Jkb, M, N, S, s

If the absorbing cells are Enzyme treated, you…

Can detect those antibodies as they won’t be picked up