immunohematology - reagents

specificity

reagents must meet _____ standards, meaning the recognition of the antigenic determinant and its corresponding antibody

potency

reagents must meet _____ standards, meaning the strength of the reaction

quality control

testing to determine the accuracy and precision of equipment, reagents, and procedures

potentiators

reagents used to enhance agglutination reactions, enhance the detection of IgG antibodies

antisera

reagents used that have known antibodies

RBCs

reagents used that have known antigens

antiglobulin reagents

reagents that are anti IgG or anti complement

low ionic strength saline (LISS)

potentiator that increases the rate of antibody uptake

polyethylene glycol (PEG)

potentiator that concentrates the antibody in the test environment in LISS

proteolytic enzymes (papain and ficin)

potentiators that remove negative charges from the red cell membrane, which reduces the zeta potential and denatures some of the red cell antigens

bovine serum albumin (BSA)

potentiator that reduces the repulsion between cells but does not shorten the incubation time

monoclonal antibodies

antibody reagent that is made from single clones of B cells that secrete antibodies of the same specificity; recognize a single epitope (Anti-A, Anti-C, Anti-IgG)

polyclonal antibodies

antibody reagents made from several different clones of B cells that secrete antibodies of different specificities (antihuman globulin/AHG)

polyclonal antibodies

produced by an animal after exposure to an antigen such as a rabbit

anti-A antisera

directed toward A antigen and agglutination indicates the presence of A antigen on RBCs

anti-B antisera

directed toward B antigen and agglutination indicates the presence of B antigen on RBCs

blue

what color is anti-A?

yellow

what color is anti-B?

clear

what color is anti-AB?

false positive

a negative reagent control for D antigen typing ensures that a _____ result has not occurred

high protein anti-D reagents

contain polyclonal antibodies, approximately 20% bovine albumin, promotes false positive agglutination

low protein anti-D reagents

contain monoclonal antibodies (IgM) or monoclonal and polyclonal blends, approximately 6% bovine albumin, typically called monoclonal control or gamma clone control

controls

ensure that typing results are correct

NO

shoudl valid controls show agglutination?

antigens

commercial reagent RBCs contain known _____ to confirm the presence of antibodies in patient serum or plasma

A1 and B cells

combined with the patient’s serum or plasma to determine the reverse grouping

screening cells

used in antibody screen tests for unexpected antibodies

antigram

each lot of screening cells comes with an _____ that shows the antigen profile

panel cells

similar to screening cells except they are obtained in vials of 10 or more; used for identifying antibodies in a procedure called an antibody panel

A2 and O cells

reagents used in work ups of ABO discrepancies

CorQC red cells

reagents used to QC most common antisera

check cells/coombs control cells

reagents used to verify function of AHG reagents

globulin

serum protein fraction containing antibodies and complement

antiglobulin test

detects presence of RBCs which have been sensitized with IgG antibodies and complement protiens, but have not caused visible agglutination

polyspecific AHG

antiglobulin reagent that contains both anti-IgG and anti-C3d antibodies, derived from polyclonal or monoclonal sources, agglutination indicates that IgG or complement is coating the RBCs

monospecific AHG

antiglobulin reagent that caontains either anti-IgG or anti-C3b/C3d but not both, anti-IgG combines with human gamma chains, detects complement proteins as a resilt of activation of the classical pathway

antiglobulin test

commercial antibody with a specificity toward human globulins is used to agglutinate antibody coated RBCs

direct antiglobulin test (DAT)

detects IgG or complement bound to RBCs in vivo, AHG reagent is added after the RBCs have been washed, agglutination demonstrates whether IgG or complement was attached to the RBCs IN VIVO

elution

if DAT is positive, then an _____ may be performed which is where the antibody is removed from RBCs and collected in a diluent, this can be used to ID antibody specificity

indirect antiglobulin test (IAT)

detects IgG or complement bound to RBCs in vitro, antibodies are incubated at 37C with RBC antigens in vitro and then washed and combined with AHG reagent to detect agglutination

IgG sensitized cells

commercial reagents are type O RBCs prepared with IgG antibodies attached, control when AHG results are negative

direct antiglobulin test (DAT)

which antiglobulin test is one step and polyspecific AHG?

indirect antiglobulin test (IAG)

which antiglobulin test is two step and monospecific AHG?

lectins

seed extracts that have specificity toward certain RBC antigens, bind to carbohydrates determinants of RBC antigens