Blood Bank II Unit #1

ABO discrepancy

when a reaction pattern does not match during forward or reverse typing

Technical Error - Identification

wrong blood in tube or labeled/documented wrong. Can be false pos or neg

False Positive

Bacterial Growth

false pos or neg

improper washing (general)

False neg

improper washing at AHG

false neg

under centrifugation

false pos

over centrifugation

False pos and neg

specimen drawn over IV

false pos

incubation temp is too cold

false neg

incubation temp is too hot

false neg

prozone/postzone

Rules out Technical Errors

clerical check and repeat test on original sample

Forward: Missing or Weak Rxn

least common. Caused by age, disease, subgroups, or trasnplants

Stronger Anti-A Rxn

weaker anti-H lectin in subgroup

Anti-A1 Lectin

only reacts with the Anti-A subgroup

Forward: Missing or Weak Rxn Resolution

incubate room temp 15-30min. Incubate 4C 15 - 30min. Lectins. Read micro

Rouleaux

abnormal amounts of plasma protein, appear as stack of coins. Extra forward rxn and reverse

Rouleaux Resolution

wash RBC with saline multiple times

Whartons Jelly

Gelatinous tissue contaminant found on cord blood. Extra forward rxn

Wharton Jelly Resolution

wash RBC 3-4 time with saline (more wash may be needed)

Cold Agglutinins

cold autoantibodies that bind to and clump RBC. Extra forward rxn.

Cold Agglutinins Resolution

wash RBC using warm saline. Prewarm. Perform partial elution using EGA or chloroquine

Polyagglutination

bacteria alters RBC membrane exposing T antigen. Forward Extra Rxn

Polyagglutination Resolution

Test patient RBC with a control. Pos is poly. Neg is AB pos

Acquired B

Patient is group A (acetylgalactosamine) but alteration in sugar resembles B (D-galactose). Forward Extra Rxn

Acquired B Resolution

Test with acidified monoclonal/polyclonal reagent. Perform autocontrol

B(A) Phenotype

autosomal dominant phenotype that occurs when B populations have elevated galactosyltransferase. Forward extra rxn

B(A) Phenotype Resolution

Test patient RBC with alternate monoclonal anti-A without MHO4

Chimerism

two different RBC populations present in one person. Found in transfusions, transplants, and fraternal twins

Mixed-Field Reaction

both agglutinated and unagglutinated cells. Caused by two distinct cell populations, bone marrow transplant, Stem cell transplant, A3 phenotype

A3 Phenotype

phenotype that most commonly causes a mixed field reaction to occur

Reverse: Missing or weak Rxn Resolution

incubate room temp 15-30min. Incubate 4C 15 - 30min. Lectins. Read micro

Reverse: Weak or Missing Rxn

Caused by age, disease, dilution with IV, plasma exchange, and dimorphic RBC populations

Subgroup of A

Groups as A in forward and O in reverse. Anti-A1 differentiates from non-A1 groups. Extra rxn in reverse

Subgroup of A Resolution

subtyping with A1 lectin and testing with other cells. All neg patient is subgroup of A

Cold Autoantibodies

antibodies specific for autologous antigen that react at room temp or below. auto control will be pos. Extra rxn reverse

Cold Autoantibodies Resolution

prewarm technique, or cold audoadsorption

Cold alloantibodies

Antibodies specific for human RBC antigen that react at room temp or below. auto control will be neg. Extra rxn reverse

Cold Alloantibodies Resolution

Prewarm technique. Antibody ID at RT or 4C

Intravenous Immune Globulin (IVIG)

broad collection of pooled antibody collected from many donors. causing extra rxn reverse

IVIG Resolution

adsorption