c. Cell-Testing on a Slide. Slide tests should be done according to the
directions for the specific anti-serum used. Some manufacturers recommend using
whole blood; others specify a 10% suspension of the cells in serum, plasma, or saline.
Instructions that apply to all slide tests are:
Label the sections of the slide to identify the antiserums.
Mix cells and antiserums gently but thoroughly over an area about 1 inch
(3) Use a separate, clean stick to mix cells with each antiserum. Do not
place slide on or over a warmed view box.
(4) Keep cell-serum mixture in continuous, gentle motion and observe for 2
minutes before concluding that agglutination is absent. Do not confuse drying around
the edges with agglutination. Avoid touching the cell-serum mixture with fingers.
d. Serum Tests in Tubes. Most serums have antibodies strong enough to
cause prompt agglutination. The cells for serum-testing should either be commercial
cells that meet Bureau of Biologics (BOB) requirements, or a 2 to 5 percent suspension of
washed cells in saline, prepared freshly each day.
Place two drops of serum into each of two properly identified tubes.
Add one drop of A cells to the A tube, and one drop of B cells to the B tube.
Use cells known to be A1 or a pool of at least five randomly selected A donors.
(3) Mix by gentle shaking. To enhance agglutination, tubes may be
incubated five minutes or more at room temperature.
Centrifuge at speed and time determined to be optimal.
(5) Observe supernatant fluid against a well-lighted white back-ground, for
presence of hemolysis.
(6) Gently disperse cell button and inspect for agglutination, using a well-
e. Interpretation of Routine ABO Tests. Table 2-6 gives the results and
interpretations of routine ABO serum and cell-testing. Note the different frequencies of
ABO groups in different segments of the US population.