Lab Manual Definitions Flashcards
Absorption
removal of an unwanted antibody.
Adsorption
providing an antibody with its corresponding antigen under optimal conditions so that the antibody will attach to the antigen, thereby removing the antibody from the serum
Affinity
the bond between a single antigenic determinant and an individual combining site. A measure of the binding strength of an antibody for its epitope; a binding constant.
Agglutination
the clumping together of red blood cells or any particulate matter resulting from interaction of antibody with its corresponding antigen.
Agglutinin
an antibody that agglutinates cells.
Agglutinogen
a substance that stimulates the production of an agglutinin, thereby acting as an antigen.
Allele
one of two or more different genes that may occupy a specific locus on a chromosome.
Allo-
prefix indicating differences within a species (e.g., an alloantibody is produced in one individual against the red cell antigens of another individual).
Amorph
a gene that does not appear to produce a detectable antigen; a silent gene.
Anti- A1 lectin
a reagent anti-A1 serum produced from the seeds of the plant Dolichos biflorus ; reacts with A1 cells but not with A subgroups.
Anti-B lectin
a reagent anti-B serum produced from the seeds of the plant Bandeiraea simplicifolia.
Antibody Screen
testing the patient’s serum with group O reagent red cells in an effort to detect atypical antibodies.
Anti-H lectin
a reagent anti-H produced from the seeds of the plant Ulex europaeus.
Antihuman globulin test (AGT)
test to ascertain the presence or absence or red cell coating by immunoglobulin G or complement, or both; uses a xenoantibody (rabbit antihuman serum) to act as a bridge between sensitized cells, thus yielding agglutination as a positive result.
Antihuman serum
an antibody prepared in rabbits or other suitable animals that is directed against human immunoglobulin or complement, or both; used to perform the antihuman globulin or Coomb’s test. The serum may be either polyspecific or monospecific.
Antiserum
a reagent source of antibody, as in a commercial antiserum.
Autologous control
testing the patient’s serum with his or her own cells in an effort to detect autoantibody activity.
Avidity
the strength with which a multivalent antibody binds to a multivalent antigen.
Biphasic
reactivity occurring in two phases.
Chimera
an individual who possesses a mixed cell population.
Cis position
the location of two or more genes on the same chromosome of a homologous pair.
Codominant
a pair of genes in which neither is dominant over the other; that is, they are both expressed.
Coomb’s serum
see antihuman serum.
Dosage
a phenomenon whereby an antibody reacts more strongly with a red cell carrying a double dose (homozygous inheritance of the appropriate gene) than with a red cell carrying a single dose (heterozygous inheritance) of an antigen.
Elution
a process whereby cells that are coated with antibody are treated in such a manner as to disrupt the bonds between the antigen and antibody. The freed antibody is collected in an inert diluent such as saline or 7% albumin. This antibody serum then can be tested to identify its specificity using routine methods. The mechanism to free the antibody may be physical (heating, shaking) or chemical (ether, acid), and the harvested antibody-containing fluid is called an eluate.
Enzyme treatment
a procedure in which red blood cells are incubated with an enzyme solution that cleaves some of the membrane’s glycoproteins, then washed free of the enzyme, and used in serologic testing. Enzyme treatment cleaves some antigens and exposes others.
Ficin
a proteolytic enzyme derived from the fig.
Genotype
an individual’s actual genetic makeup.
Hemolysin
an antibody that activates complement, leading to cell lysis.
Homozygous
possessing a pair of identical alleles.
In vitro
outside the living body, as in a laboratory setting.
In vivo
inside the living body.
Isogglutinins
Also called isoantibodies,the ABO antibodies anti-A, anti-B, and anti-A,B, which are expected to be found in serum.
Lectin
proteins present in plants (usually seeds), which bind specifically to carbohydrate determinants and agglutinate erythrocytes through their cell surface of oligosaccharide determinants.
Low ionic strength solution (LISS)
a type of potentiating medium in use for serologic testing. Reducing the ionic strength of the red cell suspending medium increases the affinity of the antigen for its corresponding antibody such that sensitivity can be increased and incubation time decreased. LISS contains glycine or glucose in addition to saline.
Major crossmatch
compatibility testing procedure using recipient’s serum and donor red cells.
Minor crossmatch
compatibility testing procedure using recipient’s red cells and donor’s serum.
Monoclonal
antibody derived from a single ancestral antibody-producing parent cell.
Phenotype
the outward expression of genes ( e.g. a blood type). On blood cells, serologically demonstrable antigens constitute the phenotype, except those sugar sites that are determined by transferases.
Prozone
incomplete lattice formation caused by an excess of antibody molecules relative to the number of antigen sites, resulting in false-negative reactions.
Xeno-
prefix indicating differing species. For example, a xenoantibody is an antibody produced in one species against an antigen present in another species. Synonym is hetero-.
Antenatal
Occurring before birth
Antithetical
Referring to antigens that are the product of allelic gene (e.g. K and k)
Heterozygous
possessing different alleles at a given locus
