Antibody Detection and Identification Lecture Review

A complete set of vocabulary flashcards covering the detection and identification of red blood cell antibodies according to the lecture materials provided.

Antibody Screen

A test using reagent Group O RBCs against patient plasma or serum to detect unexpected antibodies in patients needing transfusion, pregnant women, or donors.

Clinically Significant Antibodies

Usually IgG antibodies that react best at $37\,\text{°C}$ and during the AHG phase (IAT), associated with hemolytic transfusion reactions and HDFN.

Screening Cells

Single or pooled donor Group O cells phenotyped for 18 required antigens, including D, C, E, c, e, M, N, S, s, P1, Lea, Leb, K, k, Jka, Jkb, Fya, and Fyb.

Antigram

A sheet that lists the specific antigens present in each vial of screening or panel cells used for interpreting results.

Autocontrol

A test of the patient's serum against their own RBCs, incubated with the antibody screen or panel to help differentiate between alloantibodies and autoantibodies.

Direct Antiglobulin Test (DAT)

A procedure used to detect IgG or complement proteins bound to patient cells in vivo, requiring the washing of red cells to remove unbound proteins before adding AHG reagent.

Potentiators

Reagents used to enhance antigen-antibody reactions, including low-ionic-strength solution (LISS), bovine serum albumin (BSA), polyethylene glycol (PEG), and proteolytic enzymes.

Antibody Panel

An extended version of an antibody screen consisting of 10 to 20 antigen-typed Group O cells used to record and interpret antibody specificity.

Rule of Three

The requirement that 3 antigen-positive cells must react and 3 antigen-negative cells must not react with patient serum to ensure valid identification results.

Proteolytic Enzymes

Substances used to eliminate activity of Duffy and MNS antigens while enhancing the activity of Rh, Kidd, and Lewis antigens.

High-Frequency Antigens

Antigens that occur in the population at a frequency of $98\%$ or higher, such as the k antigen.

Low-Frequency Antigens

Antigens with low occurrence; associated antibodies include anti-Cw, anti-Wra, anti-V, anti-Cob, anti-Bga, anti-Kpa, and anti-Lua.

High-Titer, Low-Avidity Antibodies

Antibodies to high-frequency antigens that react weakly and inconsistently at the AHG phase and are not implicated in transfusion reactions or HDFN.

Cold Alloantibodies

IgM antibodies that react during immediate-spin crossmatching, such as anti-P1, anti-M, and anti-N, which are generally not clinically significant.

Cold Autoantibodies

Typical antibodies (such as anti-I, anti-H, and anti-IH) that react during immediate-spin crossmatching and may be associated with Mycoplasma pneumoniae or infectious mononucleosis.

Prewarming

A technique involving the separate incubation of serum and cells at $37\,\text{°C}$ before mixing to avoid reactivity from cold autoantibodies.

Adsorption

Techniques using known red cells (REST, autoadsorption, or allogeneic adsorption) to remove specific antibodies from a sample to identify underlying alloantibodies.

Elution

A procedure used to detach IgG from RBCs when a DAT is positive; the resulting recovered antibody is called the eluate.

ZZAP

A combination of enzymes and dithiothreitol used to pretreat red cells to remove in vivo attached antibodies.

Chloroquine Diphosphate

A reagent used to disassociate IgG from RBCs without harming antigens, allowing for the phenotyping of cells coated with IgG.

Drug-Independent Mechanism

A drug-induced serologic manifestation where the DAT, screen, and panel are positive, resembling a warm autoantibody in vitro.

Drug-Dependent Mechanism

A drug-induced event where the DAT is positive, but the serum is nonreactive with screen and panel cells unless the drug is added to the test.