AHG/Coombs/Enhanced Ab Detection

LISS

Reduce zeta potential

Albumin

Increase collisions

Bromelin

Reduce steric hindrance

Polybrene

Polymer nonspecific binding

PEG (Polyethylene Glycol)

Remove water volume

Coombs False Positives

- proteins in plasma sample

- fibrin strands in plasma sample

- antibodies attached in vivo to cells

- bacterial contamination of RBCs

- patient developed antibody to preservative

Coombs False Negative

- No agglutination @ AHG step = incorrect ratio of plasma to RBCs

- No agglutination with check cells = leftover antibody bound to check cells

Affinity

Attraction & fit

Avidity

Strength of bond

Indirect Testing

Test what has attached to the cell in vitro

Direct Testing

Test what is on the cell in the body

Coombs Test

Test for antibodies attached to cells in vivo (DAT)

Antibody ID

Logical problem utilizing known cells & patient plasma to ID source of unexpected reactivity in an antibody screen (IAT)

Extended Crossmatch

Serologic testing between donor cells & patient plasma utilized at body temperature (IAT only)

Type & Crossmatch

ABO type + Rh type + Antibody Screen + Serological test between donor cells and patient plasma

Antibody Screen

Test for presence of clinically significant immune stimulated antibodies in patient plasma

Blood Type

ABO Type + Rh Type on patient red cells

Reverse Cells

- mixture of donors

- blood type A or B

- in preservative solution (no plasma)

Screen Cells

- single donor

- blood type O

- known antigens

- in preservative solution (no plasma)