Pre-Transfusion and Compatibility Testing

These flashcards cover the vocabulary and key concepts of pre-transfusion and compatibility testing, including crossmatching phases, antibody screening, and laboratory procedures.

Pre-transfusion testing

The use of serologic principles and tests to ensure compatibility and prevent an immune-mediated hemolytic transfusion reaction.

Crossmatch

The testing of a patient's serum (containing antibodies) with donor red blood cells (containing antigens) to confirm compatibility.

Minor blood groups

Blood group systems other than ABO and Rh, including Lewis, MNS, P, Kidd, and Duffy, which can cause unexpected antibodies.

Delta checking

The process of checking a patient's current blood typing results against previous results to ensure consistency.

Replacement donor policy

A policy used by blood stations like EVMC or Red Cross where a blood unit is provided on the condition that a donor is found to replace it with the same blood type.

Universal donor

Blood type O, which according to references like Harmening, is considered a choice for all blood types, though same-type transfusion is preferred.

Universal recipient

Blood type AB, which is capable of receiving blood from any ABO blood group.

Delayed HTR

A hemolytic transfusion reaction that occurs when red blood cells have short survival times, despite being compatible during initial crossmatching.

Washing RBCs

A process performed three times to remove excess plasma and unbound antibodies prior to the AHG phase.

Immediate Spin/Saline Phase

The initial phase of serologic crossmatch used to detect IgM class antibodies that react best at low temperatures.

Thermal Phase/Protein Phase

The phase in crossmatching where the sample is incubated at $37^{\circ}C$ to mimic the body's internal environment.

LISS (Low Ionic Strength Solution)

A solution that weakens the zeta potential of red blood cells so they can be easily dispersed or agglutinated.

Antihuman Globulin (AHG) Reagent

A reagent containing IgG antibodies used to induce agglutination in positive samples or enhance the negative result in the Coomb's phase.

Check cells

Red blood cells coated with IgG antibodies used to verify that the AHG reagent was added and is functioning correctly.

pH range for Ag-Ab binding

The optimal pH for antigen-antibody binding during testing, which is $6.9$ to $7.5$, reflecting the normal body pH of $7.35$ to $7.45$.

Gel Technology

A method developed by Dr. Yves Lapierre in 1985 that uses controlled centrifugation of RBCs through a dextran acrylamide gel to trap agglutinated cells.

Antibody screening

The testing of a patient’s serum against commercially prepared Group O screening cells to detect unexpected antibodies other than anti-A and anti-B.

Screening Cells

Phenotyped Group O cell suspensions used in antibody screening to ensure naturally occurring anti-A or anti-B do not interfere with detection.

Autologous control

Testing the patient's serum against their own red blood cells to identify autoantibodies or a positive direct antiglobulin test (DAT).

IgM Antibodies

A class of antibodies, such as anti-N, anti-I, and anti-P, that react best at cold temperatures during the immediate spin reading.

IgG Antibodies

A class of antibodies, such as anti-Rh, Kell, Kidd, and Duffy, that react best at the AHG phase at $37^{\circ}C$.

Rouleaux formation

An appearance where RBCs stack like coins; it can be differentiated from agglutination by adding NSS, which disperses the cells if it is just Rouleaux.