saline agglutination sdl

what is agglutination

abnormalitiy where rbc clump together

why does agglutination happen

in the presence of antibodies on the rbc surface

• imha

in mismatched blood transfusions

what are rouleaux

• stack like formations of rbc

when does rouleaux form

in the presence of hyperglobulinaemia caused by inflam or neoplasia

Q. In what small animal species is some amount of rouleaux considered normal?

cats

Q. In what large animal species may some amount of rouleaux be considered normal?

horses

how do agglutination and rouleaux look diff

§Rouleaux should be longer and stack-like

§Agglutination forms three-dimensional clusters

rouleaux or agglutination

agglutination

Rouleaux or agglutination?

both

what else is the saline agglutination test called

saline dispersion test

what is the saline agglutination test

It presumes that RBCs are already clumping on their own and we add saline to test if the clumps will disperse or not

it is just trying to break up red blood cell clumps

Rouleaux should disperse; agglutination should not

how do you carry out a saline agglutination test

1. Add one drop blood to a slide

2. Add saline

• 1-2 drops in dogs

• 3-4 drops in cats

• In both, can add up to 10 drops if concerned about persistent rouleaux

3. Gently rock slide back and forth, watching for agglutination

Q. Why do you think cat blood needs more saline to prove we have true agglutination?

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what is macroagglutination

can identify agglutination with the naked eye if blood visibly clumps together

what is microagglutination

also identify agglutination under a microscope

how can you reduce the rate of false positives in the sat

add more saline

how can we address the risk of false -ves with the sat

§we can use the direct antiglobulin test (DAT / Coombs test) – this is an external laboratory test